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wider rear tyre

Posted: Thu Apr 18, 2019 10:37 pm
by Lumpy
Has anyone experimented with wider rear tyres on their bevels?. I have read somewhere it can play havoc with steering geometry.

Re: wider rear tyre

Posted: Thu Apr 18, 2019 11:41 pm
by ducadini
Yes, it does interfere with the geometry.
Luckily the geometry of a Darmah is such that You have to do very stupid things before You get into the dangerzone.
Fitting 16" Montjuic wheels ( with 120/160 tires) made it tuck in heavily and made it VERY prone to aquaplaning.
But why bother ?
With my 18" 100 and 130 tires (Bridgestone or Metzeler) I don't mind doing 140 (km/h) on the autostrada, in the rain.
AND they look like the standard issue blackies too.

ciao
ducadini

Re: wider rear tyre

Posted: Fri Apr 19, 2019 12:56 am
by Vince
Its all down to rim size, 120 tyre fits a 2.5 rim. You can sqeeze a 130 on but any bigger distorts the tyre profile. So it starts with a bigger rim first. I have a 3.0 Boranai like Morad rear rim on my Laveda and now I can run a 140 T31 Radial Bridgestone. Thats the bigest correct profile spoked rim thats made. They make flat style rims bigger but your now entering chain run interferance zone.

Re: wider rear tyre

Posted: Fri Apr 19, 2019 9:36 pm
by Lumpy
Thanks Ducadini and Vince. Was toying with the idea for next tyre change but remember reading an article somewhere that warned against it. Might just stick with what was meant to be......................

Re: wider rear tyre

Posted: Sat May 04, 2019 8:36 am
by BevHevSteve
As said above, putting a larger than correctly sized tire on your rim changes the tire profile and decreases grip on the road. This means you end up with less rubber on the road and, you just added weight in the worst place to add weight. Its a no win situation so please don't do it.

On your Darmah you want to only use this combo to get the best handling (in my opinion).

Front - 100/90-18
Rear - 120/90-18 (130/80-18 will have the same circumference but is really meant for a larger 3" rim)