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Raw Striker with 13" wheels. Chassis Mods?
w4lrus - 30/10/11 at 09:27 AM

In this thread in the BEC forum, towards the end, it looks like that I might need to get a Raw Striker's chassis modded to get it to take 13" wheels.

Searching around, the general consensus seems to be that 13" wheels are the best for handling on a striker, so can anybody expand on the chassis mods required, if they are required for a road going car?

Or will I be fine with 15" wheels after all?

Or have I (most likely!) got the wrong end of the stick?

Thanks in advance
Tom

daniel mason - 30/10/11 at 09:36 AM

One thing to consider is diff ratio mate. If your running 13" rims on a bec instead of a larger 15" rim then you may need to alter diff ratios to suit. And the basic point I'm making is that if you need a 3.14:1 diff to compensate for the smaller rolling radius it can get expensive. Where as 3.62:1 LSD can be got for reasonable money. A 3.38:1 will be somewhere in between.
If you have to mod the chassis and then buy a far more expensive diff it might not be worth it from a financial point of view! A lot run 14" or 15" and are perfectly fine

adithorp - 30/10/11 at 09:54 AM

13" wheels with higher profile tyres will give you better ride, grip, braking and acceleration in a light car. The higher profile most run largely elliminates difference in rolling radius. Lots of Strikers are running 13" and I've not heard of chassis mods to accomodate them. I suspect the mods refered to in that thread are more to do with the best geometry for the lower ride height used RGB racing compared to a road car.

w4lrus - 30/10/11 at 11:23 AM

adithorp, that makes sense now I think about it - Raw provide a race chassis which has a lower ride height, and i think the original thread referred to that. Great, I can proceed with my plan to use 13" wheels

The diff ratio is looking expensive however I view it - 3.14/3.38 ratios seem nearly impossible to find, and I will still need to make them limited slip I believe.

loggyboy - 30/10/11 at 04:37 PM

IIRC from when I ordered my striker, its a 'COST' option to have it suitable for 13s, however I am not sure what the acctuall mod is. I assume it was down to requiring different brake components and maybe a different rear hub. I call to Callum, Jeremy or Martin at Raw is probly the quickest way to be sure!

rdodger - 30/10/11 at 04:45 PM

195/50 15 and 205/60 13 have the same rolling circumference of 1757mm

185/60/13 is 1684mm so a bit different but since the rears are the same I don't see the issue?


Tyre size calculator

loggyboy - 31/10/11 at 08:42 AM

quote:
Originally posted by rdodger
195/50 15 and 205/60 13 have the same rolling circumference of 1757mm

185/60/13 is 1684mm so a bit different but since the rears are the same I don't see the issue?


Tyre size calculator

I would expect its not about clearance around the outside, its about clearance on the inside, smaller wheels need small brakes, calipers and possibly suspension arms/connections etc etc.

adithorp - 31/10/11 at 08:59 AM

quote:
Originally posted by w4lrus
adithorp, that makes sense now I think about it - Raw provide a race chassis which has a lower ride height, and i think the original thread referred to that. Great, I can proceed with my plan to use 13" wheels

The diff ratio is looking expensive however I view it - 3.14/3.38 ratios seem nearly impossible to find, and I will still need to make them limited slip I believe.


The other option is 3.21/1 Freelander diff. You need a quaife unit if you want LSD and it needs custom/hybrid drive shafts. Thats what I'm running. With the '06 R1 it is a bit high geared at times and gives a loooong first (72mph at the limiter). There are upsides to that, like reasonable motorway cruising revs and on twisty/hairpin mountain roads I can stay in first all the way to 13750rpm when others are up and down the 'box.

Some cars rear uprights foul on 13" wheels (don't know if the Striker does) so that maybe something that makes a difference but I'm sure RAW could advise.