What is the Largest tire I can fit on a stock rim? [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: What is the Largest tire I can fit on a stock rim?


ka2mbp
09-11-2005, 10:32 PM
Hello, I am looking to replace the tires on my 2002 Trailblazer LTZ. It currently has 245/70/17's on it. I am looking to go as tall as possible. I am not looking to change my rims right now. I am looking to fill the wheel wells as much possible without rubbing. I need to use mud and snow tires as I snowmobile up in Old Forge, NY and I can be driving in as much as 8 inches of snow on the road on a good day. Can I fit a 275/70/17 on there. It is a 31.7 inch high tire and the places I deal with around me will only put stock on. If I go bigger I can return them. Thanks for your help.

Nick

homertime
09-11-2005, 11:29 PM
Sorry nick I don't have an answer, but here's a better question that could address both of our concerns:

Can someone explain the whole rim/tire sizing thing in a thread, or even this thread?
It seems that there is a very limited amount of tires that I can put on my stock 17's, so wanted to know what sizes are safe to go to.


But kinda to address your question: I thought the "70" was to indicate the sidewall height, not the "245"... So I think you're looking for something greater then 70, not greater than 245... I think 245 indicates the distance from the sides of the sidewalls (the width of the tire)
So anyone with some expertise in this field help us out!

ScarabEpic22
09-11-2005, 11:34 PM
I just had my tires replaced a few weeks ago, and I was doing research for about 3 months before I bought them. I am pretty sure the 245 stands for the tire width. The 70 stands for the sidewall height in relationship to the width of the tire, and the final number is the rim diameter.

So, my LT tires with P245-70R16 tires have a tire width of 245 (mm?), and the sidewall height is 70% of the 245, and my rims are 16 inches.

Hope this helps clear things up!

the roadie
09-11-2005, 11:35 PM
This question has been discussed in previous threads, searchable.

I just put on 265/70/17 but they would have hit the upper control arm without 1.5" spacers. Also the SupensionMaxx lift spacers are useful.

275/70/17 might have also fit with a bit more rubbing on the wheel well liners. Who makes 275/70/17? Are you looking for A/T or off road tread?

ka2mbp
09-12-2005, 09:34 PM
Thanks for the quick responses. You are correct the 245 is how wide and the 70 is the height determined by the % of the width. So the height of our tire if 171.5 mm high (from rim to the edge of the tire). The tire rack says that the stock tire is 245/65/17 and it is 29.7 inches high. I was looking at the 265/65/17 because it is only 30.6 inches high. I really wanted to go to 265/70/17 but it grows to 31.7 inches high and I really donít see that fitting under the truck without a lift. I also want to go a little wider because tall skinny tires just look like crap. The 245ís are 8.9 inches wide and the 265s are 9.7 inches. Next year I will probably put a lift on the truck but the tires are a little thin now and I can see wasting money on tires to dump them in the spring. I just ordered the Borla Dual Exhaust and Factory Running Boards so the lift cant happen now. If anyone has tried the 265/65/17s please let me know. Thanks guys.

the roadie
09-13-2005, 02:07 PM
The tire rack says that the stock tire is 245/65/17 and it is 29.7 inches high. I was looking at the 265/65/17 because it is only 30.6 inches high... The 245ís are 8.9 inches wide and the 265s are 9.7 inches.

Looking at where the edge of the tire will be, adding 0.45" radius and 0.4" tread width (from centerline) will (by Pythagoras' theorem) make the inside edge of the tire grow about 0.60" towards the upper control arm. I think I had only about 0.75" gap on my original tires there, so your proposed size might fit.

If it wasn't for that upper control arm, I'd be running 33"s instead of 32"s. :-)

But there's no substitute for making measurements - see how much room you already have without adding spacers. To get more margin, you might be able to get away with 1/4" shim spacers (just flat aluminum) instead of the large spacers with studs of their own.

ka2mbp
09-13-2005, 09:55 PM
Looking at where the edge of the tire will be, adding 0.45" radius and 0.4" tread width (from centerline) will (by Pythagoras' theorem) make the inside edge of the tire grow about 0.60" towards the upper control arm. I think I had only about 0.75" gap on my original tires there, so your proposed size might fit.

If it wasn't for that upper control arm, I'd be running 33"s instead of 32"s. :-)

But there's no substitute for making measurements - see how much room you already have without adding spacers. To get more margin, you might be able to get away with 1/4" shim spacers (just flat aluminum) instead of the large spacers with studs of their own.

Yeah your right. Maybe I should check at a dealer on a new truck, Sunce my tires are worn it would not be a true measure. I have to check when I get home. I travel for work and have not been home in 3 weeks. I will check Friday morning. When I get this figured out I will let you all know what I finally did. Thanks again for all your help.

blu ya
09-30-2005, 04:26 PM
I just installed 265/65/17 on stock GM 2005 rims. I had about a 1/4 inch of space between the tire and upper control arm. I would say that if you go 265/70/17 like I wanted to do, it would surely rub.
My :m2: though.

Tim

XDemonX
05-03-2006, 04:16 PM
My future plans include lifting my TB to fit some BFGoodrich M/T 33s, but a lift for Trailblazers/Envoy's is as easy to find as a metiorite in a gravel pit. I've been digging around tho and found this http://www.custommotorsports.com/cmsindex.cfm?sus=b .

That's $3Gs for only a 6 inch lift and another $400 for 3 inch body lift...that makes over $3500 for 9 inches total and that's not even all suspension lift compared to around $2000 for other brands (around) 10 inch Silverado lifts...."Not Fair!" I cry! SO I think I'll stick with performance mods to handle the big rubbers until I can get a 10" suspension kit fabricated somewhere whenever I get the $$.

The point is: If you're worried about bigger tires fitting, get a lift fabricated somewhere.

Then tell the place there's PLENTY of people looking for Trailvoy kits at a good price and that'll help qual many people's worries about big tires and where to get a good, not-over-priced lift kit. Keep in mind that bigger tires require more HP and Torque to keep good performance so if you can't fit the tires you want, work on the performance side of it first. Just food for thought, hope it's insightful to SOMEONE at least! :p Take care all!

the roadie
05-03-2006, 05:52 PM
My future plans include lifting my TB to fit some BFGoodrich M/T 33s, but a lift for Trailblazers/Envoy's is as easy to find as a metiorite in a gravel pit. I've been digging around tho and found this http://www.custommotorsports.com/cmsindex.cfm?sus=b .


I think that page is there only because they didn't take it off, but it's not linked from their main site. I emailed them a few weeks ago and they claim to not offer the product anymore. I think the few they sold (3" suspension lifts) had problems destroying the CV joints.

That's $3Gs for only a 6 inch lift and another $400 for 3 inch body lift...that makes over $3500 for 9 inches total and that's not even all suspension lift compared to around $2000 for other brands (around) 10 inch Silverado lifts...."Not Fair!" I cry! SO I think I'll stick with performance mods to handle the big rubbers until I can get a 10" suspension kit fabricated somewhere whenever I get the $$.

I discussed exactly this with multiple lift vendors at the San Diego 4X4 show last weekend. Nobody believes there's a market. And they don't believe any serious offroader would buy a vehicle with the bloody front differential designed to bolt to the SIDE of the bloody oil pan and run an axle shaft THROUGH to the other side so you can't easily relocate the diff on a lowering bracket.

The point is: If you're worried about bigger tires fitting, get a lift fabricated somewhere.

That's the consensus. Or buy a really worthy vehicle and use the Envoy to TOW it to the trails. ;)

Then tell the place there's PLENTY of people looking for Trailvoy kits at a good price and that'll help qual many people's worries about big tires and where to get a good, not-over-priced lift kit.

What's PLENTY to you and me is not PLENTY to the lift manufacturers. Call 'em NOW if you want them to count your vote and create a product.

Sheesh, they make lift kits for frickin' Jeep LIBERTYs (which are to real Jeeps as the SPECIAL Olympics are to the real Olympics) but not for Trailblazers and Envoys. Talk to the lift designers. They really have no respect for us.

Keep in mind that bigger tires require more HP and Torque to keep good performance so if you can't fit the tires you want, work on the performance side of it first. Just food for thought, hope it's insightful to SOMEONE at least! :p Take care all!

I appreciate the post, but in rock crawling, it's not all about power. Not at all. I sometimes ride shotgun with a 4-banger heavily-modified Jeep. With a first gear ratio of 3.93, a modified transfer case running 4-to-1, and 5.13 ring and pinions in the differentials, that's about an 80-to-1 crawl ratio. He runs 35" tires, and would only go bigger if he had more engine. BUT, he can go up a 25 degree trail in first gear low while IDLING!

With too much torque, the weak spots will be the front axle CV joints and possibly the rear axle shafts. Neither of which have a lot (like any) aftermarket support for upgrades.

My focus now is not getting much more of a lift, but protecting the vehicle I've already got with custom fabricated bumpers and rock rails (neither of which are offered by any bumper place - it's not just lifts where we're ignored). Sometimes I don't know anymore why I bother.:sleepy: