I have a set of S Lites coming and I am considering putting 205 40 17 Kumho's on them. These would be 1/2 inch less in overall diameter. My question is what will this do for alignment geometry?

I have had tire wear problems on other independent rear suspension cars when changing the tire diameter very much. Will this cause a problem and will the 40's be like riding on wagon wheels?

Thanks for your feedback.

 

205/40s are not ideal.

Link

 

>>I have a set of S Lites coming and I am considering putting 205 40 17 Kumho's on them. These would be 1/2 inch less in overall diameter. My question is what will this do for alignment geometry?
>>
>>I have had tire wear problems on other independent rear suspension cars when changing the tire diameter very much. Will this cause a problem and will the 40's be like riding on wagon wheels?
>>
>>Thanks for your feedback.

Don't know what you mean by wagon wheels. I have run 205/45R17 on my Cooper and wore those babies out, now I have 215/40R17 Toyo Proxes-4 and have not had any alignment problems. On the weekends, I swap the 17's out for 205/50R15 Falken's for autocross and then back to the 17's for week day driving.

paddy

 

What I mean by wagon wheel is that it seems like they would be EXTREMELY firm. I have never had a tire with a lower profile than a 50. It seems like going to a 40 would be such a low profile that there would be no flex at all.

The only reason I'm considering them is that it would lower the car ever so slightly and be almost two % shorter than the 15's that are on it, giving the car effectively a slightly lower gear.

The 205 45 17's are a 1/4" in diameter larger than the 175 65 15's that are now on the car.

Thanks for the comments.

 

>>I have a set of S Lites coming and I am considering putting 205 40 17 Kumho's on them. These would be 1/2 inch less in overall diameter. My question is what will this do for alignment geometry?

I don't think you will have much difference in alignment if you have the stock MC suspension. What you propose will work OK. The 205/40 size has a slightly lower load rating than the 205/45-17 that came with the S-lytes so don't overload your MC with four heavy people and their luggage for a month's trip.

>>I have had tire wear problems on other independent rear suspension cars when changing the tire diameter very much. Will this cause a problem and will the 40's be like riding on wagon wheels?

Assuming that your current alignment is within specs you should be OK. If you have altered the suspension with lowering springs then all bets are off as you might have more rear negative camber- hard to say without checking but you cannot adjust rear neg camber without installing adjustable rear control arms (bottom pair).

I'd say you should do OK. The 40 series tires are stiff but they are not runflats and if you have stock suspension then it is also not as stiff as H-sport springs so you should be OK. I run 45 series Yokohama ES100s and it is a bit rough but mostly pretty smooth. Not bad.

If you have lowered springs then the 40 series tires will be a bit rough. Just be careful to avoid all potholes. Go slow over bumps and in unfamiliar areas or when it rains and when puddles are really large holes.

One of the problems with 17" wheels for the MC using stock rims is the stock 205/45-17 size is hard to find. Much easier getting 215/45-17 which works OK or the smaller 215/40-17 (lower load rating)- either size will also work.

 

Unless your car is lowered at least 1.5inches, your ride is going to look pretty
wierd.

 

>>Unless your car is lowered at least 1.5inches, your ride is going to look pretty
>>wierd.
>>

How and which post is your response directed at??? Just want to know.....

 

=> I have a set of S Lites coming and I am considering putting 205 40 17 Kumho's on them. These would be 1/2 inch less in overall diameter. My question is what will this do for alignment geometry

 

>>=> I have a set of S Lites coming and I am considering putting 205 40 17 Kumho's on them. These would be 1/2 inch less in overall diameter. My question is what will this do for alignment geometry

This is the setup i run 17" wheels with 205/40/17 on an MCS

potholes... beware.

I am not lowered - and the look is fine for what I LIKE. that said, I'll probably switch to 205/45/17 when the time arises...

Also, it is VERY VERY rough. IMHO, rougher than runflats.

I run parada spec-2's

 

>>>>=> I have a set of S Lites coming and I am considering putting 205 40 17 Kumho's on them. These would be 1/2 inch less in overall diameter. My question is what will this do for alignment geometry
>>
>>This is the setup i run 17" wheels with 205/40/17 on an MCS
>>
>>potholes... beware.
For the MINI using 17" wheels you always have to watch out for potholes.
Bad for the runflats, bad for the rims since the force is transmitted to the rims since the runflat side walls are so stiff. It's a little better with 16" rims and with taller side profile tires like more than 50 series.

>>I am not lowered - and the look is fine for what I LIKE. that said, I'll probably switch to 205/45/17 when the time arises...

The look of the wheels in the wheel arches is totally subjective. If you like the non lowered look then great. If you like the very lowered look then you'd need some springs or coilovers. You do get a bit more lowered center of gravity and cornering advantage with the lower setup.

>>Also, it is VERY VERY rough. IMHO, rougher than runflats.
>>
>>I run parada spec-2's
Parada spec 2s are a bit rougher riding and the 40 series is stiff so that is why you are saying it is rougher than runflats. We have some MCS owners with 215/40-17 Potenza S-03 pole position tires and doing very well with some roughness but not as bad as stock runflat 17" tires.

The perceived roughness or harshness is a little subjective based on your past experience with performance wheels. For those who are used to stock cars and normal wheels it can be quite a change. But in the sizes you mentioned the non runflats in 45 series is still good performance and pretty safe for ride quality on smooth roads.