Oh Yes! A new tyre thread!

In the Shed
1

Hi chappies, On my FF at the moment I’ve got old Macadams Size 110/80-18 and 140/80-17 on the rear. I was going to try some Dunlop Streetsmart tyres in these sizes but after reading some old threads on here some of you have successfully used 150/70 on your rears. This intrigues me because my go to tyre on my Tiger is the Dunlop Roadsmart III which is available in those sizes.

Sooooo…

Does anyone see any problem using these tyres on the comstars? I believe the 150/70 is acceptable on the 3.5" rim.

Thanks Lads

2

No problem using a 150/70 on the rear Pete Johnboy Graham and myself are all using one
Regards Bif

3

I’ve used oversized radials for several years on my Bol D’or without issue. No problem with clearance, and they seem to perform as well as, if not better than, conventional sized cross-ply tyres (BT 45). I went for Pirelli Angels, 110/80 x 19 and 150/70 x 17. The only thing I had to consider was suspension settings due to the softer carcass of the radial over the stiffer carcass of the cross-ply. I initially went with the recommended pressure, 36psi and 42psi. I have since lowered pressure to 34 and 38psi, which is my current preference.

4

Check out Mitas just fitted one to my vf1000fe on the rear ,it feels great and sticky
£75 on offer at the time, they make in all popular sizes
top Make in Europe from a huge company

5

Thanks for all your advice buddies, i’ll take a punt on my favourite Dunlop Roadsmarts.

Cheerts
andy

6

On my Fe I put ON a 150/70 (given to me) instead of Stock 140/80-17.
Realize the Circumference will be different;

TireProfile.jpg808×274

I whip’d up this chart quick-like, so probably not accurate, but you can see the differences.

My Cruising RPMs went way up, so had to change rear sprocket to a 41T from stock 43T, to return RPMs to “normal”.


If I do this more, I’ll even change to a 40T,… I like Taller Gearing.

7

Thanks fe,
useful info there, personally I think I might like the lower gearing for a bit of increased acceleration!
Cheers all,
Andy

8

A 7mm reduction in rolling radius is hardly noticeable,difference between a new and worn 140/80 if you want a comparison
Regards Bif

9

Rather than gearing, my (brief) consideration was ride height and how this would affect the geometry…though it’s worth pointing out my F2 is hardly a track bike :wink:
Bif makes an excellent point about the difference between new and worn tyres, which technically also affect ride height.
By my calculations the switch to lower profile tyres resulted in an axle drop of 2mm at the front, and 7mm at the rear. If I wanted to I could have added 5mm ride height at the rear to balance out the difference. However I’m happy with the result and have left it that way.