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[Xiaofeng]

Hi everyone,

I'm currently looking at getting new tires and wheels for my car, and I'm really liking the CSL replicas. However, I'm coming across a bit of an unexpected problem. Since these cars don't have spares, and since the tire goop that comes with the BMW Mobility Kits will most likely damage the TPMS sensors, I'm opting to stick with run flat tires. Unfortunately, that's where my problem comes in.

Based on the specs of the CSL reps, the wheels are 18" x 8.5" and the recommended tire size is 235/40-R18. Apparently, virtually no one makes a run flat tire in that size, so I was wondering if it would be okay to put on 225/40-R18 tires, which it seems is the recommended tire size for many 18" x 8.5" wheels (according to Tire Rack's web site). Would this cause any problems?

Any assistance or insight would be greatly appreciated! Thank you in advance!

[BMW F22]

225 will be a little stretched but it will be fine.

[david @ eas]

Wouldn't be a problem at all, except a little stretched as Kenny says... But why do you want to stay with the RFT?? Most people want to throw those away as soon as you get the car

[Xiaofeng]

Thanks for the replies, guys. So when you say stretched, are you saying that the sidewall will actually be stretched wider than the tread width, as in the tire will look like this from the front?

\__/ (Not quite that exaggerated)

Will this have any adverse effect on either the tire or the handling of the vehicle?

It seems that most tires that I see are "compressed" into the rim, resulting in a tire that looks like this:

/__\ (Not quite that exaggerated)

If stretching the 225 will make the sidewall angle more vertical, I'd be okay with that, but if it actually bows outward, I'd be a bit worried about premature tire wear.

[david @ eas]

Yes you have the idea of what we mean by stretched... the tire isn't really overlapping the wheel, or I guess you can say overflowing over the lip of the wheel, but the complete opposite. Here's a picture:



This picture IS NOT what it's going to look like whatsoever. This is a crazy example just so you know what we are talking about. How the tire is just too small for the wheel all together. Hope this helps!

[Xiaofeng]

Originally Posted by jurrian @ eas

Wouldn't be a problem at all, except a little stretched as Kenny says... But why do you want to stay with the RFT?? Most people want to throw those away as soon as you get the car

Jurrian,

I'm looking for RFT tires primarily because I don't want to be stranded anywhere waiting for a tow truck should anything happen. Since these cars have no spares, and since we can't use the mobility kits because the latex goop clogs the TPMS sensors, that doesn't leave me with many options. What are you guys running non-RFTs doing to prevent from being stranded?

[VMRWheels]

An alternative to the mobility kits are space saver spare tires with tool kits. You can purchase them from online stores like Leather Z. This is what is looks like when placed in the trunk of a E90:

[Xiaofeng]

Originally Posted by jurrian @ eas

Yes you have the idea of what we mean by stretched... the tire isn't really overlapping the wheel, or I guess you can say overflowing over the lip of the wheel, but the complete opposite. Here's a picture:

Thanks for the clarification, Jurrian. So in this particular case, how much would the 225 be stretched on a CSL rep? Is it still pretty much vertical, or will it be noticeably stretched? If the difference is only a few millimeters on each side, I wouldn't have a problem, but if it's greater than, say, a centimeter, then I'd be worried that the corner treads of the tire would wear out prematurely, and the handling of the vehicle would be compromised.

[BMW!]

CSL reps has 8.5 width and a 235/245 tire would be good for it. If you go with 225 the tire will not wrap the edge of your wheels, means your wheels will be sticking out a tiny bit. Why can't you just get the 235?

[Xiaofeng]

Originally Posted by BMW!

CSL reps has 8.5 width and a 235/245 tire would be good for it. If you go with 225 the tire will not wrap the edge of your wheels, means your wheels will be sticking out a tiny bit. Why can't you just get the 235?

Unfortunately, I can't seem to find anyone that makes a RFT tire in a 235/40-R18 tire size, hence my dilemma. If I could pick up performance RFT tires in that size, this thread probably wouldn't exist, and I'd already be ordering the wheels from one of our vendors here.

[VMRWheels]

Don't worry. 225/40/18 is completely fine on our 18x8.5" wheel. The tire will have a slightly rounder profile, but it is completely safe and you won't have any problems with it.

[Xiaofeng]

Thanks for the help, everyone.

Somewhat along the same lines, has anyone used one of those tire plug kits before?

http://www.amazon.com/Slime-2040-A-T...8741520&sr=1-1

Perhaps something like this can be a good alternative to the tire goop, so long as the repair will stay until the tire has a chance to be professionally repaired. If they work well, it might be better to simply carry one of these and use the correct 235/40-R18 non-run-flat tires. Anyone carry around one of these kits instead of the latex goop? How well do they work?

[Xiaofeng]

* for new question.*

I did some chatting with some buddies, and they seem to think that if I want to stay with RFT tires, I might be better off getting 245/35-R18 or 245/40-R18 tires. Since the CSL reps are 18"x8.5" wide, 245 width tires should fit properly, right?

Also, what would be the proper offset for a E90? Looks like the wheels are only available in 20mm and 40mm offsets, and some quick calculations on the tool at the top of the page shows that using a 40mm offset is probably the more plausible solution, but by losing 12mm on the strut side, will I have to worry about rubbing on the inside of the tire, especially since I'd be running a wider than recommended tire?

Primarily, I'm just worried about the front tires, as I don't anticipate the rears having any trouble.

Thanks again for the help!

[ModBargains.com]

Originally Posted by Xiaofeng

* for new question.*

I did some chatting with some buddies, and they seem to think that if I want to stay with RFT tires, I might be better off getting 245/35-R18 or 245/40-R18 tires. Since the CSL reps are 18"x8.5" wide, 245 width tires should fit properly, right?

Also, what would be the proper offset for a E90? Looks like the wheels are only available in 20mm and 40mm offsets, and some quick calculations on the tool at the top of the page shows that using a 40mm offset is probably the more plausible solution, but by losing 12mm on the strut side, will I have to worry about rubbing on the inside of the tire, especially since I'd be running a wider than recommended tire?

Primarily, I'm just worried about the front tires, as I don't anticipate the rears having any trouble.

Thanks again for the help!

Hello!
With RFTs, you should be better off with 245/35/18 tires. With the 18x8.5 CSLs with ET40 offset, you won't have to worry about any rubbing on the fender or struts. We have customers that go with 18"x8.5" with ET35 offsets with their E90 with our M6 wheels, and they don't experience any rubbing/fitment issues. 40mm offsets are fine though, it just won't set as aggressive as the ET35 offset would--still looks amazing.

Rears and fronts will be fine, so don't sweat

[VMRWheels]

Originally Posted by Xiaofeng

* for new question.*

I did some chatting with some buddies, and they seem to think that if I want to stay with RFT tires, I might be better off getting 245/35-R18 or 245/40-R18 tires. Since the CSL reps are 18"x8.5" wide, 245 width tires should fit properly, right?

Also, what would be the proper offset for a E90? Looks like the wheels are only available in 20mm and 40mm offsets, and some quick calculations on the tool at the top of the page shows that using a 40mm offset is probably the more plausible solution, but by losing 12mm on the strut side, will I have to worry about rubbing on the inside of the tire, especially since I'd be running a wider than recommended tire?

Primarily, I'm just worried about the front tires, as I don't anticipate the rears having any trouble.

Thanks again for the help!

Yes, you'll be fine with the 8.5" ET40 up front. You should go with a 245/35/18 if you want to use a 245 width. The only RFT I could find in that size is the Bridgestone RE050A RFT. They are fairly expensive at $327 a tire and have a tread wear rating of 140. Anyhow, if you're still set on getting RFT, the Bridgestone tires seem to be your only option