Slot.it Wheel Dimensions

[Slotspeed]

Not sure how the Slot.it tyre measurement system works. I had a look at the Slot.it tyre selector but that was pretty useless and minimal measurements were listed. I am looking at these wheels:

 

http://www.armchairracer.com.au/workshop/wheels/slot-it-wheels-pa20-als-f1-1-0gr-aluminum-14-5-x-12mm-std-hub

 

I am assuming the 14.4mm refers to the bead diameter, but I am not entirely sure. I am assuming the 11.5mm refers to tyre width, and not including the spigot width. (I guess that's what the 12mm is that Armchair are referring to) So scaling the photo I get approx 6mm internal tyre step width. I would normally just contact the shop but they are moving today and tomorrow so probably not a good time!

 

Cheers for any clarification.

Steve.

[SlotsNZ]

Not sure what chart you were using, this is the current one.

14.4mm is the diameter of the centre diameter.

 

So the correct tyres are those of the DWG 1068 size - any of their F1 tyres

If you want to use another brand tyre you'll just need to check dimensions, but in general, the step height and width on Slot.it and most other brands for modern F1 are so similar they are mostly interchangeable.

 

But if you want F1 wheels and tyres for an older F1 car, the Policar F1 wheel and tyres are slightly larger - 16 x 11.7 and have C1 and F22 formula tyres to match.

 

[Slotspeed]

Hey thanks for that. Assuming by center diamater that you mean the external rim size rather than the internal size for the removable plastic centre? Yes that was the chart I had looked at. Its a little frustrating as other manufacturers seem to give more info away regarding the sizes of the step, step depth, overall diameter including step, etc etc. I have some NSR F1 tyres which I am hoping to use, but failing that, I will have the perfect rims to suit the Slot.It tyres. The wheels are for one of my Carrera 917k's. I machined one set down to suit NSR F1 tyres (Overall diameter of the step was too deep before machining) but wanted to try Slot.it wheels on the second car. Going to see if a Slot.It crown, axle and bearings will fit while I'm at it. Will solve a few problems in one go hopefully.

[SlotsNZ]

Now I hear your situation - you are probably better buying a complete Slot.it "kit" for that car. It works out cheaper than individual bits. I have no idea what a "removable plastic centre" is. These are primarily alloy wheels.

 

Slot.it have tried to simplify the matter into a "these fit those" system rather than have everyone trying to figure out all the dimensions.

- You obviously have a maths and numbers brain, but a lot of the people I deal with can't get their heads around a whole lot of data sets (4) for widths of centre, overall wheel width, width of boss, step height. Then you need to understand that a given tyre will fit a couple of wheel sizes or more, and they often need to know the O.D. with THAT tyre fitted, or another tyre fitted, to check it suits what they want...

Their brains just fuse and they want a simple answer. The chart provides all the information in a grid system - just look across and look down, choose the size wheel you want, the tyre compound you want, and the O.D. you want.

No other maker does that.

 

You don't really need to worry about width of the centre, and how deep the step down is, because the main alloy wheels and aftermarket tyre makers are very similar. I can take any NSR tyre and fit it to the same nominal O.D. and width Slot.it wheel, and vice versa. All you really need is the O.D. the width of the rim - typically a nominal 8 or 10mm, and the width of the boss if distance between the outside of axle bush and inside of wheel arch is restrictive.

 

Slot.it parts are probably the simplest way forward - their range is pretty broad and readily available; and there are several other makers using the same axle diameter, same gears modulus and same gear diameters, so you still have the ability to mix and match brands to a fair extent when you are scratching around your war chest to sort out bits for a car.

 

I suggest you measure

1) the O.D. of the centre - which is probably between 16.5 - 17.3mm

2) The width of the wheel excluding the boss probably 10 - 12mm

3) the width of the wheel including the boss

4) The width of the wheel with tyre fitted - to check you will end up with a usable O.D. with the new alloy wheels.

 

You can then choose probably a 9.75/10mm GT type wheel (not the one you were looking at which was an F1 wheel), just as wheels, or as part of a kit; and choose a tyre to suit it.

If the car is an inline the KK03 for older cars, or KK17 kit might be a good choice

 

I am not familiar enough with their sidewinder setups to know if one using the same bush as Scalextric and 18mm or 19mm spurs will suit..

[Slotspeed]

I think you are Mark?

 

Thanks for your considerate reply. I like your logic, and enjoy talking about this kind of stuff. I checked the Slot.It kits and the closest one was the Scalextric F1 kit, but the crown gear was only 24T, I need 26T at minimum as the slimline Carrera motor struggles to produce the required torque with the stock gearing as it is. I have ordered a 27T crown, hoping it is going to help slightly. The stock pinion is 8T, and Slot.it don't make an 8T brass pinion for a 1.5mm motor shaft which is a bit of a pain. I am just going to have to run the original nylon pinion for now and upgrade to the 8T 1.5mm shaft brass pinion available from Pendle's later. If I go to the Slot.It 9T, the gearing will be too high for the motor. 9T/30T would have been a good ratio to try, but I don't think the 30T is going to fit inside the housing without getting the dremel out. And I haven't found the dremel since moving house twice! Which also makes me wonder how the outer diameter of the tyre is going to work out on the selected wheel!

 

Check this out... Porsche 917k side view

 

And Porsche 917k rear view

 

The profile/aspect ratio and width of the rear tyres is huge! And seem to be approximate to F1 tyres of the same era... Interesting! If I want to keep the look close to scale, the closest choice is F1 tyres. Paul Gage has a tyre that fit the original wheels, but I don't like the Urethane tyres on plastic track (which is what I am running on) I needed to at some stage upgrade the axle from the Carrera original, so I had to build up the axle kit from parts. According to a chart from a Canadian retailer, the NSR F1 tyres will fit the Slot.it PA20-ALS wheel that I mentioned earlier, but I like things to be just right, and the tyre is 13mm width, and we are talking about probably an effective 11.5mm wide rim, so it will be interesting to see what the overhang looks like. The Carrera wheels sit well inside the body and this is not very true to scale, the 1:1 car barely has any clearance at all to the rear tyres, so it will be nice to be able to adjust the rear track for correct scale width and probably enhance the handling at the same time. Of course, I could just swap to a different wheel diameter and lower profile tyre if predictable handling is what I want! The car goes ok but bounces around a bit with the big, soft tyres at the moment.

 

So basically I am waiting now for the wheels to arrive to see how it all fits together! And how the NSR tyres seat on the wheel and if I need to reduce the diamater of the tyres a little bit. Probably not though. I can simply try the appropriate Slot.it tyre if need be, maybe it will be better for my needs. Looking forward also to better tolerancing on the axle bearings.

 

Cheers,

Steve.

 

Oh and one last thing, Pendle's have a nice looking air wheel that would probably fit nicely, but its 10UKP plus postage and I have already ordered the mentioned wheels and spent a bit too much improving the car from stock!

 

I will also measure everything up and post it here when I have the opportunity, just for the sake of it.

Edited June 21, 2018 by Slotspeed

[SlotsNZ]

Cheers Steve, yes, I think I am Mark, - but my label fell off, so I cant be certain

Okay, I understand now that you're trying to keep the look with high profile tyres right, not just the O.D.

 

Those NSR tyres should fit fine on the Slot.it F1 hybs - even if there WAS some very small difference on rib heights, that stopped the surface from being flat right across the width, it would sand out easily as you trued the tyres - - - you do true your tyres...... ?

That bit of extra real "track" gained at the same time by fixing the wheels as far out as possible will help the handling of that heavy Carrera 917 a lot as well, let alone the accuracy of the better wheels/tyres.

- If you are keeping the original axle - what diameter is it, and was it splined like a Scaley, or smooth - I am pretty ignorant on Carrera, we haven't had much of it here in NZ from the distributors, who are more a toys company interested in TV and film related merchandise.

Yeah, Carrera motors have about the same torque figure as a drunken ant trying to decide which way is home. Rumour has it one once pulled the skin off a rice pudding and was banned for excess performance.

 

So long as the nylon pinion meshes okay with the 27t crown it should last fine, you may not need the change. But you can also get 5 packs of replacement 8 tooth nylon pinons for less than 7 bucks from a forum sponsor, which are 0.5 modulus, and for sure will mesh fine with the Slot.it gears. Far be it from me to tell you which one. you'll have to hunt

[Slotspeed]

Oh that's great news about the pinions Thank you for the tip. I also bought a couple of cheap ebay slim can motors and would like to compare them to the Carrera motors. I'm guessing they might be similar in performance.

 

Perhaps I shouldn't be so worried about the scale look. I couldn't actually get the 27T crown from my local supplier, but I was able to get a slot.it axle kit KK08B with the same crown gear for $20 which had the bonus inclusion of two slot.it bushes and a 51mm axle which will no doubt get used for something else. Comes with a couple of bonus plastic wheels, again might get used for something. The standard Carrera axles are horribly splined things, axle shaft diameter of about 2.28mm. The standard bushings are approx 3.35mm so would need reaming to use them with the slot.it axles. The standard bearing clearance is excessive and leads to horrible chatter. The reason for the excessive clearance is so that the bushings clear over the splines for the wheels. ARRRGGHHHHH! What a horrible idea! I understand that they are really aiming at a different market but really?! I thought about trying to remove the original crown gear from the axle and re-using it, but I'm not confident I could drill or ream out the hole with the required accuracy to avoid run-out when assembled on the new axle. I also ordered two 45mm slot.it 2.38mm axles plus the wheels so I should be all set. It's really all a bit silly since I could have bought a really good car for the sum total! One of my 917k's will retain the original running gear, for now. As mentioned, it already has modified original wheels.

 

Cheers!

 

Oh and yes, I do a poor mans method of trueing the tyres, it seems to work ok. Some of my cars were undriveable before I used this method, so it must work kinda. And the 917k isn't too bad on the weight for what it is. Its a much smaller hunk of plastic than a sedan or sports sedan and comes in at about 84grams. They look bigger than they are.

Edited June 21, 2018 by Slotspeed

[SlotsNZ]

It's usually the same when we try to take a model designed fairly and squarely by a "set maker" for what we call the toy market, and set it up to run half way decent non-magnet - especially on wood.

Usually costs more in parts to turn a Scalex Muscle car into a club machine than it cost to build in the first place.

 

ff-050 motors are all pretty low torque. They simply don't have the strength of magnet to convert un-powered resistance into braking. Gearing tall as you intend to do is one way to help.

If you have a dremel type tool, any weight you can remove from the insides of the body or interior will help a lot. The lighter the rolling unit, the better the motor can pull it up of course.

I have often cut away most of the invisible parts of the "glass", drilled the driver hollow, and generally ground as much plastic out of the inside of the body and the interior as possible.

 

Making sure what brakes are there can be used in good tyre grip is also useful.

 

I am just not sure of the fit of axle bushes for Scalex into any of the Carrera chassis - their O.D. may be different. But if they can be used, the options get a bit wider for you.

 

For gears, as well as Slot.it; Slotting Plus, ScaleAuto, and Avant Slot are all the same axle hole sizing, and all 0.5 modulus based teeth spacing, so should all mesh fine. You may find some of those around.

So are MR Slotcars Canada and SRC "Chrono" (they make a 27 tooth crown in both alloy and brass), but pretty sure no one in Oz every carried either of their aftermarket spares.

 

There are still some old Ninco "EVO 32 crowns about, they mesh "okay-ish" - they just weren't great quality. Probably a few other brands as well, but that gives a few options.

[Slotspeed]

Interesting. Yes, I think the common modern Scalextric bushing OD is the same or very similar to the Carrera bushing. Slot.it list a Carrera/Scalextric upgrade bushing that is the same part for both makes. I've seen PA64 set of 4 available at the bigger retailers.

 

Edit: I also said earlier that the NSR F1 tyres were 13mm wide. I just measured one and it was more like 12.3mm. The tread itself is more like 11mm. So a good chance that they will be a good match for the Slot.It 11.5mm wide rims.

Edited June 21, 2018 by Slotspeed

[Slotspeed]

Ok, so the Slot.it wheels arrived from Armchair Racer. I ordered the day that they were moving. So was expecting the order to take a while. But it only took a few days by regular auspost to get here! Quite impressive that they were able to move the order during a busy time like that.

 

To my surprise, the diameter that is used by Slot.it (14.4mm in this case) to describe this rim is actually the outer diameter of the wheel including the step. That leaves the tyre inner diameter (bead as I like to call it, I'm sure there is a better name) at 12mm. Which is a bit on the small side for my application. (Original wheel is 13mm on both front and back) so it is going to look a bit odd from a scale model point of view, but I'm hoping it will be ok from a performance point of view. Apart from that, the tyres I was planning to use fit just fine. The OD of the mounted tyre is 1mm smaller than original for the car. So my overall gearing will be slightly lower, but I'm more worried about the ride height dropping that 0.5mm. The rear of the chassis already sits slightly lower than the front as standard, thanks to the Carrera track rails sitting slightly higher than the track surface, though new set up will be a slightly lower CG. Shut up and put the wheels on I hear someone say! Will be fun to see how this goes!

 

Here is my sketch of the wheel dimensions...

 

(Edit... the small black thing is the plastic insert that comes with this wheel)

 

Edited June 26, 2018 by Slotspeed

[SlotsNZ]

Yep, that's why I was questioning you buying F1 hubs and tyres instead of the GT wheels and tyres, but you indicated you wanted a scale look with high profile tyres.

I normally call the outside part the "shoulders"

[Wobble]

Not only will you have better grip but you'll have better brakes and acceleration too and if you paint the alloy hub black the slightly smaller size will be less noticeable.

[Slotspeed]

Yep, that's why I was questioning you buying F1 hubs and tyres instead of the GT wheels and tyres, but you indicated you wanted a scale look with high profile tyres.

I normally call the outside part the "shoulders"

 

Yes, fair point.

 

Not only will you have better grip but you'll have better brakes and acceleration too and if you paint the alloy hub black the slightly smaller size will be less noticeable.

 

Wobble, you referring to the slightly smaller diameter tyre? The original car had black rims so that would be pretty close in looks.

 

I just found out last night that NSR used to produce Porsche 917 1/32 cars. Had I known that, I would have gone looking for those wheels. I have found the tyres that were fitted to those models, but not the wheels yet. I have three Carrera 917k's in total, one has original rims machined down to suit other makes of tyre, the one we have been talking about will probably end up with the Slot.it wheels for a while, and I do have one more 917k model that is as yet fully stock, so I guess third time lucky perhaps. I don't plan to spend more money on it right away, its more of a gradual thing.

 

Edit: Here is the NSR 917k rim. They look perfect though the diameter might be a bit larger than scale, but who would notice! I'm guessing they would be difficult to obtain.

 

 

Also, looking back at the Slot.it tyre reference chart, if I am reading it correctly, I have a couple of options there as well for a more correct final diameter. I will check the retailers to see who has what available, depending on how I go testing with the parts I already have. I guess I should have paid more attention, at the time I thought the tyre/wheel combination I had chosen was likely going to be a hit. Mark, you also pointed this out!

Edited June 26, 2018 by Slotspeed

[Wobble]

"Wobble, you referring to the slightly smaller diameter tyre?" … yep that's the one Slotspeed as the smaller dia wheel is similar to lower overall ratio.

 

I think there are still plenty of NSR 917K's floating around. You might be interested in this -

http://www.nsrslot.i...ls/917/917.html

Edited June 26, 2018 by Wobble

[Slotspeed]

Wow, how did I miss that! I hadn't seen that model until I chanced on a post about it last night. Thanks for the link.

[Slotspeed]

Interesting as the wheel reference http://www.nsrslot.it/spare/cerchi/tabella_cerchi_1024.jpg shows the standard wheel for the NSR 917k to be the 5002 which is only 8mm wide. Though the specified tyre is 11mm wide. These tyre and wheel sizing conventions are quite confusing. Unless the reference table is wrong maybe. I think I better just stick what I have on and see how it goes. If it goes well just be done with it!

[SlotsNZ]

Tyres are always wider than the rims they fit. - Mostly 2mm wider, but if you want a bit more bulge in your tyre wall, or are working with tyres that are isometrical (the inside thin bit is offset from left to right), it may be 1.5mm over hang.

[Slotspeed]

Looking at a photo of the underside of the NSR version of this car (easy to find photos on evilbay!) the wheels chosen by NSR are definately on the skinny side, and not very scale looking! Thanks for the tip Mark.

Edited June 27, 2018 by Slotspeed

[Slotspeed]

Assembled and test drove. Didn't use the Slot.it crown gear after all. It had an extra 3grams on the original crown gear. I managed to remove the original and ream and glue it to the new slot.it axle and it was still intact and as true running as it was on the original axle. Re-used the original Carrera bushings, they were pretty much the same ID as the slot.it bushings. Trued the tyres.

 

On the (plastic) track:

Lower drive ratio very noticeble, even though I only lost 1mm overall diameter from original wheel/tyre combo, makes a big difference.

Car stays slotted when wheels set for wider track but a horrible driving experience. Though it looks and feels much faster (compared directly against my other Carrera car with original wheels but with same NSR tyres as this one)

Narrowed the track by 2mm as a test.

Car more controllable in the corners but it bounces around horribly when getting too hot in the corners. Not a nice experience, Tried a softer NSR compound, even worse!

 

I noticed my wife to be's Sideways Hurracan has a wheel/tyre combo that has perfect outer dimensions for this application, those tyres are very soft and pliable, even while on the rims. (The hurracan handles any plastic track anomolies or inconsistencies like they are not even there! Though obviously the suspension on the hurracan is nothing like a Carrera car) Next experiment will be to swap them onto the 917k and see how it goes. Getting close to your first suggestion Mark, priority is the car needs to be driveable! Looks are second! Other option is to machine the original wheels like I did for the first car. But I don't have access to a lathe anymore.

Edited June 27, 2018 by Slotspeed

[SlotsNZ]

This will be an interesting learning curve for you, you'll gain a lot from this process.

But to help narrow the suspects

- Part of your problem is simply that you have a heavy Carrera body, and higher COG, but the bouncing is still most likely caused by the wheels/tyres being out of round, and/or slop in the rear axle bushes.

Unless it has absolutely no wriggle at all, the bush/axle combination needs the big 86 and the matching buses/axles fitted.

 

The lower gearing is unlikely to have very much bearing on handling, and if you have that low torque ff050 motor, that is probably a help unless you have a track with really long straights.

 

One thing you may want to try, is using hot glue (which is easily removable), to ensure the motor is locked in place and cannot twist, and perhaps brace the back axle bush holders to the chassis and motor - as a temporary solution for testing, it can be as simple as more hot glue and some matches or tooth picks. Those together will reduce twisting of the chassis due to torque from the motor.

- And you really will need to true those tyres by some method - preferably after gluing to the rims with a glue that doesn't react with the tyre compound.

Some super-glues will cause NSR (and other brands of soft rubber) tyres to degrade and split

[Slotspeed]

Overall weight is 90grams, 6 grams higher than my other Carrera 917k, there is a little bit of counter weight in the back, might be slightly more than the other car has. But most of the extra weight is probably the Carrera digital chip and connectors. But yes, body is quite heavy. The tyres have been trued, albeit poor mans method, but not a problem on other cars that have had the same treatment. Bushes tested with GO/NOGO method and are very very close, very little slop at all. They are less than 2.40 and greater than 2.38mm so perfect (about the same clearance as the slot.it bushes) Slot.it axle that has been fitted measured with micrometer at exactly 2.38mm

 

Bushes were previously glued, could do it again. Not sure what is meant by the "Big 86" ?

 

Just tried it with the Sideways Hurracan wheels/tyres, closer to the original diameter 21mm, at 20.65mm after trueing and only slightly narrower at about 10.6mm width. The car is handling more smoothly, more driveable and predictable, much nicer to drive. I tend to think the car dosen't like having the smaller OD wheels/tyres at all. Especially as the other 917k handles very well with the slightly larger diameter wheels with the F1 NSR tyres as mentioned (at pretty much the original 917k tyre OD). It all started because I wanted to avoid doing any machining! (the step of the original wheel OD was huge before machining on the other car) I will try glueing the motor in and re-glueing the bushings to the chassis. Maybe re-true the Hurracan tyres.

 

Will give it a break for a while as I need to concentrate on other things.

 

(edit: I just did some timed laps, the car with the new slot.it axle, and borrowed Sideways Hurracan wheels is doing on average about 1/2 second faster a lap than the other 917k. The two cars were previously on par with each other. (previous set up before the recent wheel and tyre swaps was on PGT urethanes on the original wheels and original axle and lots of bushing slop! Just for clarification, this is a magless setup with a little bit of weight just below and just before the rear axle)

 

edit: Just weighed the bodyshell and Wow! its 26grams. I can see a few spots that could be carved out a bit.

 

Thanks for walking through this with me Mark!

Edited June 28, 2018 by Slotspeed

[Slotspeed]

Got another set of tyres in the mail, NSR 5216 to go on the Sloting Plus 17mm (16.9mm) wheels. Did some testing. The following is a bit of a ramble really!!!

 

Summary:

 

Sideways 17.3mm wheels - ribbed, air system - fastest lap 5.10. Handling is really good. Overall wheel/tire diameter 20.35mm. Think the ratio is 8/26 which is what I counted, but the spec for the car says 9/27. (And yes, I am a former fitter/machinist so I do know how to count!)

 

Standard wheels but modified (machined down) to take NSR F1 supergrip tyres, Overall diameter approx 21mm. Handling - gets very sideways but very very fun to drive, and very predictable. A pair of cars set up like this probably the most fun for racing as they are very forgiving set up like this. Lap time is going to be slower, timed at 5.55 seconds, but this was with the other 917k, which is analog. The digital car I found is actually faster. This I attribute to the very very good braking of the digital car, you can hear the tyres gripping the plastic track under brakes, its very effective! Digital car running in analog mode.

 

Sloting Plus 17mm wheels with NSR 5216 Supergrip rubber: 5.24 seconds. Handling similar to sideways tyres/wheels but not as fast, and not as good. This will be a compromise. The scale look is a bit compromised. But I like that it is faster than the 917k that I have set up with the F1 tyres.

 

In closing: I learnt a lot about driving, and amazed that minor differences in wheel design seemingly make quite a bit of difference in handling, the ribbed air system providing best results of all for this particular case, though the air system would not be activated at all on this small track, I think it is more about the sidewall support and the perfect sizing of the wheel for the Sideways tyre. Also the geometry of the car is easily comprimised by putting the wrong sized wheels or tyres on it and this results in deslots for this particular model. The funny thing is I like the slower set up with the original (modified) wheels with the NSR F1 tyres the best. Its just more fun.

 

Steve.

 

edit: I will later post a couple of photos of the cars that I did the testing with

Edited July 20, 2018 by Slotspeed

[Slotspeed]

A week on and driving my other Carrera 917k was just so much more enjoyable in comparison, even though it was quite a bit slower. So I did some poor man's lathe work and machined the original wheels down to now take NSR F1 tyres. End result is ok. I'm a little annoyed that I have to retain the original axle. Which is pretty crappy and loose in the bushings. Reason I have to do that is because the original wheels are splined to go onto the Carrera splined axle. I am running a slot.it crown wheel (because I had modified the original one to go on a slot.it axle) which is also not ideal as it dosen't run all that true on the original axle. It is also quite heavy at 3 grams. The car however, is much smoother and more predictable, and slightly easier to drive. The best set up I had on this car was with the Sideways 17.3mm wheels and maybe I might try this again some day, but the scale appearance is important to me so I am happy with this setup for now.

 

(edit: I will post some photos of the poor man's lathework at some point, and the final setup)

Edited July 26, 2018 by Slotspeed

[SlotsNZ]

Slotspeed, I probably missed some things while I was away at the Nats - but if you are able to do basic lathe-work - could you machine down the Carrera rear wheels to make inserts which fit a common 16.5 or 17.3mm Slot.it alloy wheel?

That way you could use the Slot.it crown with 2.38mm axles that fit a standard bush - Slot.it also make bushes specifically for Carrera chassis.

 

- You would then use an NSR tyre which is "high profile" to get the scale tyre look. [ NSR tyres fit fine on Slot.it wheels ]

 

I am sure there is some way to keep scale appearance AND make it run really well.

[Slotspeed]

Hi Mark,

 

If I had access to a lathe, no problem. I am a qualified fitter and machinist. But am reduced to using bush machinist tools at home. Have found a wheel and tyre combo that I think will work well. Just waiting for enough other items to order to justify an order from Pendle's as no local stockists have the Policar wheel that I want to try. It's 14mm inner tyre bead diameter, 15.8 overall diameter from memory, nominal size was 16mm I think, 11.5mm wide. I have a feeling you would suggest a narrower tyre, but my other Carrera 917k handles really nicely on a 13.2 inner diameter, 16.00mm outer and 12mm width wheel with NSR Supergrips on it. It is the stock wheel machined down in diameter with makeshift machining methods, but just handles really well. The extra profile of the tyre seems to make up for the rest of the car. I will be running Slot.it axle with original crown wheel Tried Slot.it crownwheel already, but its a bit heavy as its made of brass and some kind of plastic or composite material for the gear itself. Have glued an original crownwheel onto a Slot.it axle and it performs or outperforms the Slot.it crown, probably due to the weight advantage. Have also compared the original Carrera and Slot.it aftermarket bushes, the Carrera original bush is in fact perfect on a 2.38mm shaft. I can push a 2.38mm shaft into it but not a 2.40mm shaft so that says it's spot on. Might be 0.01mm bigger inner diameter than the Slot.it bushing. The Slot.it bushing looks to be made of Bronze, but the Carrera looks to be made of brass, so obviously the Slot.it is going to be better in the long run, but the Carrera bush is not as bad as you may think it would be. The OD of the Slot.it bush I think is about 0.2mm bigger (I measured it but am going from memory here) and fits very tightly into the chassis but may negate the need for glue to help with the chassis flex issue as it is very tight.

 

Hope to be able to update with some actual testing soon, but still deciding what else to add to the OS order. For the time being I'm back onto the 17mm wheel and Slot.it axle with a 10mm wide tyre but the car kind of needs the extra flex or damping of the higher profile tyre.

 

Edit: Just an added anecdote, The chassis I am working on has a digital board which I think weighs about 3g. As a result, the car is more top heavy than my analog 917k. So it tends to roll rather than slide, compared to the other car. It does have fantastic brakes though, as the active braking is effected on the board itself when the car is running in analog mode. I assume there is a FET switching across the motor when braking. I have cut as much weight out of the bodyshell as I dare. Original body weight was... 25g. After an hour or so of cutting off anything that looked like it wasn't needed, and feeling a bit like a team Lotus mechanic after taking the washers off the cylinder heads, the weight was measured at... 25g. Yep, no measurable difference. But I did try moving some ballast around the chassis and did manage to reduce a deslot problem by putting a bit of weight up front. I guess I should have called this topic something else like Carrera digital 917k handling improvement rather than what it is currently called.

 

Cheers,

Steve.

Edited August 25, 2018 by Slotspeed