School me on running different diameter tires than stock

[killramos]

So this is me showing my clueless side but how much does it matter if you deviate from OEM tire diameters?

In this case I am talking about going less wide than stock but keeping rim diameter the same. How far can you safely/mechanically go before it will cause issues.

I just genuinely have no idea what is ok and what is not in this regard and google hasn't been enormously helpful so far.

Any rule of thumbs on % difference to stick to?

This would be on a modern car with electronics up to wazoo so need to make sure it doesn't fuck with any wheel speed sensors too much either.

TIA

[dj_rice]

The rule is to stick to max of 3% or under is best. Anymore you risk catastrophic failure LOL or its the speedo is out of whack


Thats from what I've been told working in Parts to go by at any brand Ive worked at.



Go on a tire calculator, like 1010 tires, throw in your OEM sizing and then play around with size and calculate. Stay 3% or under. I'm sure you can find stuff less wide but same overall diameter.

[killramos]

I have been finding some stuff at just under 2% smaller, wasn't sure if that was a lot or not . Would actually make things square with the OE fronts which seems like an ok compromise.

I will keep digging around. 1010 keeps crashing on me today which is frustrating.

[Kloubek]

There is lots of stuff to consider. Wheel well gap/clearance, speedo, look, handling differences, power decreases, ride height, weight, wheel rub on suspension components, etc.

If your vehicle is AWD, you also need to ensure all 4 tires are the same rolling diameter. (Or as close as possible to it).

Otherwise, despite all the things already mentioned, it really isn't a big deal to go to a different diameter. If you are a FWD or RWD vehicle and nothing is rubbing, then you are good to go. But if you aren't at least close in the diameter, then you are subject to some sort of trade-off.

As far as sensors and electronics go, I don't believe it is a big issue as long as you keep the same size all around. Unless there is another sensor in the tranny or something that conflicts with the data the wheel sensors are giving, I don't see it as an issue. Heck, I've run tires FAR bigger than stock on my Jeeps without any issues to speak of except for noticeably worse fuel economy.

If you are going with a narrower tire but keeping TIRE diameter (rim is not relevant) the same, then you shouldn't notice any mechanical or electronic issues as a result. 2% is nothing at all.

[killramos]

Luckily only rwd, going a couple % smaller should be pretty safe for rubbing, I'm not trying to stance the car or anything. Just tough finding tires is all.

Thanks guys

[JustinL]

What car is this for, and what is the application/reason for change? AWD cars are more sensitive to front rear rolling diameter differences. Square setups don't care, even a transmission speed sensor won't know the difference.

[killramos]

I'll keep the car to myself (I just don't want to jinx it until it's mine).

I'm having a tough time finding a set of GOOD winters that will fit on rims that will clear the brakes and keep diameters in line. Literally just boring old dd street use.

Have to get a bit more creative than going with stock sizes is all.

[spikerS]

Just give Tirebob a call at urban x. problem solved.

[3nergiz3d]

Originally posted by spikerS
Just give Tirebob a call at urban x. problem solved.

This. Tirebob or Jordan will straighten everything out for you.