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BEC Tyre Widths
scootz - 23/8/17 at 05:00 PM

What tyre widths are folks running on their road-going litre BEC's?

I'll be using a set of 7 x 16 rims on mine which can accommodate between 195 and 225 width tyres.

I want the car to be fun to drive, so don't want to 'over' tyre it. Besides, with only 85ft/lbs of torque, I'll hardly be setting the tarmac ablaze!

Would a 195 / 205 combo be sensible, or 205's all round, or should I really be looking at a more obvious 205 / 225 stagger?

Cheers


Neville Jones - 23/8/17 at 06:21 PM

Hello Scott!

What are you up to now?

You're right, don't over tyre it. Some of the tyre combinations I've seen are downright dangerous, and must be frightful to drive in the wet

The locost racecars seem to do ok on 185/60 road tyres. You might have a bit more power, so 195 at most.

And please, don't put big wheels with those silly super low profile tyres on, it'll ride like an old cart and feel every little ripple on the road.

It's about road pressure, and contact patch shape.

Stay alive, and be sensible.

Cheers,
Nev.

Say hello to the wife and the dog for me.


andyfiggy2002 - 24/8/17 at 07:31 AM

13" on 60 profiles seem to work well on lightweight BECs i mean when was the last time you saw low profiles on an F1 car??? a bike engine is designed for half the weight & tyre contact patch of a BEC so if your tyres are to big the clutch & gearbox are obviously going to fail quicker

westfield designed the 1300 megabusa, 1100 bird & 900 blade with much R & D so I guess their tyre recommendations must mean something hence why I'm running 185x60x13 tyres on 6x13 rims at 18psi all round on my megablade, see pop up info on link below

linky




[Edited on 24/8/17 by andyfiggy2002]


adithorp - 24/8/17 at 09:59 AM

I'm running 185/60/13 front and 205/60/13 rear. I've 2 sets of wheels; One is 6.5" front/7"rear and the others are 7"F+R. Not much difference really but I feel the 185's fit the 6.5" rim better.

Why are you going for 16" rims? I originally had 15" but swapped to 13" and the ride and grip were both better particularly on poorer surfaces. They are lighter than the 15's I had, so thats a contributory factor but it was a like for like swap I think the weight difference would be marginal.

andyfiggy, the F1 arguement is a bit of a red herring. The teams use 13" because thats what the regs say. Most teams have expressed a desire to go to at least 15" as it would give them better control of the suspension (the 13 is acting as an undamped spring).


andyfiggy2002 - 24/8/17 at 12:36 PM

Ok i stand corrected on the regs of F1, interestingly Formula E goes the other way & uses Michelin Pilot low profiles on 18"s rims where energy efficiency is more critical & therefore less tyre rolling resistance is best at the expense of being able to generate less heat from sidewall flex, then again F1 race on faster dedicated tracks whereas formula E use street circuits where cornering speeds are less.

TBH the added weight of the larger rims, the firmer ride, difficulty of getting heat into the less flexible sidewalls and higher cost of these low profiles would put me off using them on a lightweight BEC


pekwah1 - 24/8/17 at 12:50 PM

i agree, i'm running 13s also.

The larger sidewall is a good factor to let more heat get into the tyres due to flex.
If you have small stiff sidewalls, you'll struggle to warm up the tyres enough on a car as light as ours


scootz - 24/8/17 at 12:54 PM

Thanks guys - lots of good info there,

I'm using 16's as I already have a pretty set of forged fella's in my garage loft. Very light as well for their size at 5.6kg.

They also clear the braking components I have - 15's would just be a little too tight.


peter030371 - 24/8/17 at 12:58 PM

quote:
Originally posted by andyfiggy2002
Ok i stand corrected on the regs of F1, interestingly Formula E goes the other way & uses Michelin Pilot low profiles on 18"s rims where energy efficiency is more critical & therefore less tyre rolling resistance is best at the expense of being able to generate less heat from sidewall flex, then again F1 race on faster dedicated tracks whereas formula E use street circuits where cornering speeds are less.

TBH the added weight of the larger rims, the firmer ride, difficulty of getting heat into the less flexible sidewalls and higher cost of these low profiles would put me off using them on a lightweight BEC


Formula E tyre sizes are driven by the tyre manufactures. They want to develop (and be seen to develop) 'fast' tyres for the most relevant wheels size to the mass market which is now 17,18 and 19". Michelin bid on the F1 tyre contract but part of the deal (from memory) was that they would want the rules changed to 18" wheels which we all know look silly and really are not the best on a road car (of any sort)!


russbost - 24/8/17 at 01:16 PM

"Besides, with only 85ft/lbs of torque, I'll hardly be setting the tarmac ablaze!" - a common misconception, bike engines have a reduction gear, usually around 1.6:1 before the gearbox, therefore the actual torque the box receives won't be 85 ft/lbs, but more like 136. With the ZZR 1400 mid engined & on 9" rear rims with 245 or 255 17" tyres if I simply floor it in 1st even on a dry road it will light the back tyres up when it gets to around 6/7000 rpm, & again in 2nd unless tyres are already well warm. Unless you are going for proper sticky road legal "slicks" then I think it would be difficult to "over tyre" on a 7 x 16 rim all IMHO of course!


Ian2812 - 10/10/17 at 02:25 AM

I am running Toyo R888r's 205/60 r13 on minilites. I know these would be small for your case, but just put my info on in case any one else finds it helpful.

This tyre in particular is a nice and sticky road legal track day semi slicks, (also quite forgiving on public roads.)

B1257 North Yorkshire Moors TT
B1257 North Yorkshire Moors TT


[Edited on 10/10/17 by Ian2812]


CosKev3 - 10/10/17 at 06:47 AM

I'm currently running a set of 6J 14''s with 185/60 tyres whilst my 13''s are en-route and my car definitely drives much better than on the 7J 15''s with 195/55 tyres

Feels lighter all around,steering and handling wise through fast corners.


quote:
Originally posted by andyfiggy2002


TBH the added weight of the larger rims, the firmer ride, difficulty of getting heat into the less flexible sidewalls and higher cost of these low profiles would put me off using them on a lightweight BEC


You will find 13 inch tyres are more expensive than 15''s or 16''s in lower profiles.

Very little choice in tyres too in 13 inch.


Mavrik - 17/11/17 at 10:55 PM

quote:
Originally posted by scootz
What tyre widths are folks running on their road-going litre BEC's?

I'll be using a set of 7 x 16 rims on mine which can accommodate between 195 and 225 width tyres.

I want the car to be fun to drive, so don't want to 'over' tyre it. Besides, with only 85ft/lbs of torque, I'll hardly be setting the tarmac ablaze!

Would a 195 / 205 combo be sensible, or 205's all round, or should I really be looking at a more obvious 205 / 225 stagger?

Cheers


I'm running 15" Focus alloys on my MK Indyblade with 205/50/15 Avon ZZR's all round at the mo but I'm going to run a stagger on the rear... Thinking 215/50/15 in the Toyo 888 rears... I spoke to my "Tyre Guy" who races karts & he reckons a stagger is the way to go ;-)