Firstly, apologies for another thread about wheels....
I'm thinking of changing to 13s for the usual reasons of weight and reducing unsprung mass etc etc. Currently I've got a 'square'
set up of 7J rims and 195/50/15 tyres.
Looking at tyres in R13, width options seem to be 185 or 205. I'd like to change to 205/60/13 at the rear to maintain the same circumference as
my car is bike engined with a 3.62 diff so runs out of gears around 115ish at the moment and I don't want to lose anything off this. I'd
then consider 185s at the front.
Two questions then;
Is the change in widths likely to have much effect on handling?
Is it necessary to drop to 6 or 6.5J at the front if running 185s?
Thanks.
Oli
I think I've answered my own question on rim widths after looking at the toyo website, which gives a range of 5-6.5J for 185/60/13.
So would it be worth going narrower at the rear too?
I've just done what you have.
Bought a set of 13x7 team dynamics
I fitted them with 185/60/13 and 205/60/13 (front and rear) and they fit fine
As for handling, I doubt a mere mortal would tell the difference.
But narrower may be better up front as there's less weight on them. If you get a smaller contact patch you put more pressure on it which may
improve grip, there's obviously a fine balancing point for optimum weight/contact patch
Also, what brakes have you got? specifically rear ones.
You may find the handbrake mechanism and spring touch the rim.
A little tap of the handbrake arm to bend it down and a shorter spring solves this.
Someone on here sells the springs, or they can be modified yourself but it's tricky, I snapped 3 trying to do this and I was being very careful
after the first one.
I've got Sierra calipers on the rear and am aware of the issues. I bought some shortened springs from someone on here but they look about the
same as the ones I already have; hopefully the original builder has already used a shortened set.
[Edited on 9/5/17 by OliilO]
quote:
Originally posted by OliilO
I think I've answered my own question on rim widths after looking at the toyo website, which gives a range of 5-6.5J for 185/60/13.
So I have 7x13 with the 185 tyres like everyone else. Pity they stopped the 6" rim as it would have saved
more weight, about another 300g per side i think 
Compomotive CXR come in 13x6, 13x7 and 13x8 so should easily cover your needs.
quote:
Originally posted by se7ensport
Compomotive CXR come in 13x6, 13x7 and 13x8 so should easily cover your needs.
How's your sump to road clearance?
As 185/60 13's will lower the front end.
24mm lower rolling radius,so the car will be 12mm lower on the front end.
Not much,but lots of BECS don't have a lot of sump to road clearance!
The sump is almost level with the lower chassis rails, so no real concerns in that front.
I'm tempted by a set of Force wheels which would potentially solve the difficulty in finding some 6J wheels for the front.
When I moved from 15s to 13s I really didn't see any more issues with ground clearance. I have 205/60 R888s on the back and standing then at the
side of my 195/50 A539s the 13" wheels had a slightly bigger RR. The 185s on the front were very very slightly smaller.
I certainly noticed a difference is ride and handling though my old wheels were way heavier than the Prorace 1.2s I now have.
I moved from 15 to 13 with the only issue being the back wheels needed longer wheel studs and spacers to clear the upright but once that was done the
ride was much better and to me that looked much better as well..
205s on the back, 195s on the front.
For that reason my next one will have 13s from the start....