# Low profile tyres vs. small hubs



## Gareth (Mar 8, 2011)

Hi All,

I race in the UK at the Worthing HO club which Woodcote runs. 

Last night was the first round of the new Mod season where we run toy chassis (LifeLike T, Marchon MR-1, SG+, SRT, Artin F, Tyco and Mega G with upgrades to traction magnets, wheels, pickups, springs, gearing and with free choice on bodies including lexans. Basically the chassis and motor are the only stock items and are banned from being modded apart from the addition of pin tubing to the chassis. Tyres must be silicone and sponges are banned.

Anyway I have noticed that a number of the best prepared modified and pro-modified cars at National and club levels are sporting larger rims but with lower profile tyres. My cars are all currently on AJ 0.250 double flanged hubs and I use the Tyco range of Supertires from the 0.418 up to the 0.448. I'm also using Compound A which is the softer of the two.

I don't know if the real life physics of low profile tyres applies to slot cars in that the tyres are not air filled but I am hypothesising that the silicone being softer than the hub is causing my car to have increased lateral (sideways!) movement under cornering and thus increasing the chances of spinning out during high speed cornering. 

Of course this could all be a big pile of horse generated fertiliser but I'd appreciate your comments, experiences and any offerings of preferred hub suppliers and sizes. 

If it helps, I run a mixture of SG+, LL-Ts and SRTs. The SRT definitely doesn't like the 0.250 rim without a huge tyre to go with it! 

Cheers

Gareth

P.s. I have posted this on a couple of different forums as I'm really interested in garnering as much information as possible. I am happy to pass any and all knowledge gained back and forth if people want it.


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## Sir Slotsalot (Jan 23, 2010)

Gareth,

I think you are on to something good. For what it's worth. The laws of physics in 1:1 scale also apply at the modeling level. The net effects by comparison will obviously differ in magnitude with respect to actual weight, mass, etc. Anyway, if you've noticed the trends in the automotive industry that are "race car" influenced, rims are getting larger in diameter and the the tires are decreasing in sidewall area i.e; profile: the distance from the rim's outer diameter to the tire's tread.

From my own 1:1 driving experience, newer style tires with less side wall are "stiffer" handling while older style tires with more side wall are "mushy and cushy" handling. It factors the same with any given material, the longer the span of something, the more deflection. A tall tree will sway in the wind. A tree stump is not affected by the wind obviously, yet both are made of the same material. With this in mind shouldn't we be going in the same direction with slot car tires? By using tires with less side to side deflection, we could reduce unwanted "sway" issues from centrifugal force, therefore increasing the car's stability in the turns. Adjustments for track conditions could be done with tire material durometer i.e; softer for "bumps/joints" in sectional track, harder for smooth routed track. In summary, lower profile tires should provide better handling by nature. Just a thought. I'm sure others are thinking about the same thing as we speak.


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## Joe65SkylarkGS (Feb 15, 2010)

My .02 c is this, the overall tire height is most likely the same as your slip on's. The silicon that is used to coat the foam tires, is just better for handling. Better than any slip on. And if you notice, there are different compound foams too. The different color tires represent softness or stiffness.


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## Sir Slotsalot (Jan 23, 2010)

Joe,

I agree. The softer silicone coating provides better grip. In addition, I think a lower profile tire (no matter what material) by natural physics would provide better handling and take things up a notch. But, because slot cars are smaller in scale, maybe the effects would not be as dramatic as we'd like.


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## Gareth (Mar 8, 2011)

Hi Guys, 

Thanks for the answers. There is definitely something to this hub size thing! And there I was thinking that the overall diameter plus tyre compound were the only factors. 

Anyway it does go to show just how much work is involved in extracting maximum performance from a car. Three different variables on the rear wheels alone!!


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## Hornet (Dec 1, 2005)

Run the biggest hub you can get your hands on,and the shortest tire you can get away with.
Drill the hub and crown gear full of holes if you're really anal about going fast


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## cwbam (Feb 8, 2010)

What type of tracks?

Power and Torque vs. weight and friction.

big wheel and small tire weigh less.

also front end balance, tire size & springs, can really help.


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## Gareth (Mar 8, 2011)

Big (60 foot plus length) Tomy sectional tracks are what we race on with a 1.25 amps per lane, bench power supply at 18v.

I've got a quick running car but I noticed that although I'd dropped the tyre size enough to cause bogging down and sticking, the car was still slightly loose at the rear end in the corners which is why I thought of the big rims. 

I'm definitely going for it.


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## Hornet (Dec 1, 2005)

Have you got access to a tire truer.
To do what you want,you're probably going to have to grind tires.

These are my measurements on .300 double flange hubs,with compound A Supertires fitted to hubs.
These are wide tires and hubs


442 Supertire=478/480 on .300 hub.

Here's some various hubs i was gonna flog awhile ago

http://www.hobbytalk.com/bbs1/showthread.php?t=347026


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## Hornet (Dec 1, 2005)

Dug around,and i do have some soft compound "A" 418s

418= 460 on .300 dia hubs.


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## Gareth (Mar 8, 2011)

Hornet said:


> Have you got access to a tire truer.
> To do what you want,you're probably going to have to grind tires.
> 
> These are my measurements on .300 double flange hubs,with compound A Supertires fitted to hubs.
> ...



Hi Rick,

I don't have access to a tyre truer unfortunately as that would be pretty useful to have.

Thanks for these measurements. 460 is still pretty high compared to where I think the car will be able to go to which is around 430. 

I think I'm going to go with Compound B on the Supertires.

Think I need to have a little chat with woodcote about how he is achieving low profile goodness on his cars!!

Cheers

Gareth


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## Hornet (Dec 1, 2005)

Gareth take a look at the Life Like slip-ons.
They come with a slightly bigger hole,so they don't grow as much as the small hole Tyco tires do.
Stay with the soft ones,you'll get better handling out of them.
I'm not sure if you know this,but Nick's Supertires get firmer the more you stretch them.
So when you get a soft compound one stretched onto a big hub,the tire acts more like a firm tire.
Up till you get to a full on level 52 glue in style car,you'll probably prefer the soft tires,once you get to a full tilt neo car,where every mag is Neo,then the firm tires are an advantage,but till then,i'd stay with the soft versions.:thumbsup:
Rick


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## Gareth (Mar 8, 2011)

Thanks for the tip Rick. This is brilliant advice and much appreciated. I have a good stock of Tyco Supertires in compound A and a couple of sets of the LifeLike ones as well so once I get the hubs, I can start playing. 

I think I'll be getting some new 0.59 axles along with Pro Predator gears to go on them. Should be a really good backend of the car.


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## Hornet (Dec 1, 2005)

Give me a couple days,and i'll run some Life Like tires onto differant sized hubs,to give you an idea of what they'll grow to on the differant hubs.
Right now i don't have any Life Like versions in stock,but my buddy Lyle does,so i'll get some off him on Friday night.
Might save you a bit of experimenting.I've got the hubs on hand,so it's not like i'm spending money that already hasn't been spent.
Does anybody in your group have a tire truer,they are definitely an asset if you can swing one.
Rick


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## Hornet (Dec 1, 2005)

Here's some measurements of soft compound 418 A's on differant sized hubs.
These are my measurements,so only use them as a guideline,as everybody has a differant way of measuring tires.
All hubs are wide Hobby Pro's except for the JW Pro's and the 300 BSRT hubs

Hub Size Mounted Tire size

250 = 418/419

260 = 425/426

270 = 434/435

275 JW Pro's= 437/438

275 = 438/439

280 = 443/444

285 = 445/446

290 = 451/452

295 = 455/456

300 BSRT = 457/458


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## Hornet (Dec 1, 2005)

Gareth,heres my measurements of Nick's LL Supertire slip-ons mounted on hubs.
Remember though these are my measurements,so don't think they're wrote in stone,your way of measuring could be differant then mine.
So only use these sizes as a guideline.
The 442's are soft compound "A" tires,the 446's are compound "B" tires
Rick

I had them split up to where you could read them,but as soon as i post the thread,it gets hard to make heads or tails of.
I'm too lazy to re-write the post,so you'll have to study the post carefully



Hub = 442LL "A" = 446 LL "B"
Size

260 = 424/425 = 426/427

270 = 433/434 = 435/436

275 = 437/438 = 439

275 JW's = 435/436 = 438/439

280 = 441/442 = 444/445

285 = 444/445 = 449/450

290 = 447/448 = 452

295 = 452/453 = 454/455

300 = 455/456 = 458/459


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## Gareth (Mar 8, 2011)

Hi Rick,

Thanks for this. Fantastic work. I'm going to copy it all out into a handy little spreadsheet I use to keep track of my want list, track stocks etc. 

Really looking forward to trying this stuff out. And buying some digital calipers!!


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## Hornet (Dec 1, 2005)

Gareth:Calipers usually aren't the best tool for measuring tires.
They're really finicky to get a good measurement out of,with-out squashing the tire.
Calipers are a needed tool for this hobby,but for tires i prefer an actual tire gauge.
I'm not saying you can't use calipers for tires,but they are a little more time consuming to use acurately.
I'll run the bigger Tyco slip-ons that i didn't list in a bit.
Rick


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## Hornet (Dec 1, 2005)

442 Compound A Tyco slip-on measurements

Hub size = 442 Tire

250 = 439/440

260 = 450/451

270 = 457/458

275 = 464

275 JW's = 464

280 = 469

285 = 474

290 = 476

295 = 480/481

300 = 485


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## slotking (May 27, 2008)

rick, have used digital calipers for years with no problems.
just takes a little time to get used to the feel.

I like it better than the tire guage


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## Hornet (Dec 1, 2005)

Mike i still use them too yet myself at times,just to double check my tire gauge measurements. 
I actually had to use them here,i run out of decent tire gauges at 480,and had to use calipers on the last couple big measurements,that's when i remembered how finiky they are,lol.
I was just tying to give him a heads up about them,and how they take a little more time to use properly.
I try to keep things as simple as possible for the newer guys:thumbsup:
Once they have some experience under their belt,then i figure they'll have a better chance of using things right
Rick


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