M&H 275/45/18 Anyone tried them yet?
01-29-2010, 08:32 AM
#3
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
There will be a noticeably more rounded "sidewall bulge" shape with this combination than with any of the OE 17" or 18" sizes. Not a big deal if there's something about the tire performance that's most important. Just that you may or may not prefer that look the rest of the time.
Norm
01-29-2010, 12:29 PM
#6
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
Understand that a visual "fits very nicely" may or may not correspond to "best performance", even in drag racing. I realize that it's very convenient, less expensive, and not all that far "below spec" in this case. So there's some pressure to run that combination anyway. But "visual" is a pretty crude guide here, and it varies from one individual to another.
Depending on how the specific tire make/model/size was developed, it is entirely possible that even drag strip results would improve slightly with 9" wide vs 8.5". I don't think I'm guessing wildly here - by assuming that the tire carcass shape was basically designed around its so-called "measuring rim width" and that contact patch loading can be expected to get less uniform as you move either direction away from that width.
That said, I can picture a reason or two how you could force the installation on wheels slightly narrower than "measuring" to possibly be better for purely straight line acceleration, but only if they're a little bit narrower. No, I can't put any numbers on this (you'd need some rather careful testing for that).
8.5" vs 9" does not represent a border between 'pass' and 'guaranteed fail' for 265/40; tires don't work that way. If anything, 9" was a consensus point among the members of the TRA that established a boundary between acceptable and unacceptable margins of safety for unrestricted use of any tire made in that size. Unrestricted meaning any sort of normal driving, not just a few hundred feet of straight line at a time and a 10 mph turn onto the return road.
I guess that because (fortunately) drag racing is of very brief duration in a tightly controlled environment, you can get away with a lot of things that you shouldn't do in most other sorts of driving (low rear tire pressures is a sort of related item that comes to mind).
As far as the OP's immediate choice is concerned, all of this extra discussion is somewhat moot - he already has the tires ordered.
Norm
Depending on how the specific tire make/model/size was developed, it is entirely possible that even drag strip results would improve slightly with 9" wide vs 8.5". I don't think I'm guessing wildly here - by assuming that the tire carcass shape was basically designed around its so-called "measuring rim width" and that contact patch loading can be expected to get less uniform as you move either direction away from that width.
That said, I can picture a reason or two how you could force the installation on wheels slightly narrower than "measuring" to possibly be better for purely straight line acceleration, but only if they're a little bit narrower. No, I can't put any numbers on this (you'd need some rather careful testing for that).
8.5" vs 9" does not represent a border between 'pass' and 'guaranteed fail' for 265/40; tires don't work that way. If anything, 9" was a consensus point among the members of the TRA that established a boundary between acceptable and unacceptable margins of safety for unrestricted use of any tire made in that size. Unrestricted meaning any sort of normal driving, not just a few hundred feet of straight line at a time and a 10 mph turn onto the return road.
I guess that because (fortunately) drag racing is of very brief duration in a tightly controlled environment, you can get away with a lot of things that you shouldn't do in most other sorts of driving (low rear tire pressures is a sort of related item that comes to mind).
As far as the OP's immediate choice is concerned, all of this extra discussion is somewhat moot - he already has the tires ordered.
Norm
Last edited by Norm Peterson; 01-29-2010 at 12:33 PM.
01-29-2010, 01:58 PM
#7
5th Gear Member
Join Date: Oct 2009
Location: Livin in NC, from Michigan...Yooper
Posts: 2,008
Nice write up Norm, I've been hashing back and forth what I want to do this summer...Wide, tall, 19's again, 20's 18's , 275's 265's 255's, but what I'm going to do after reading all these threads, not just this one is, I'm going to 18's in a Saleen style wheel, take the recommended they suggest when I but and go with that, selling the wheel is one thing, you picking the size is another, I would have to think if they want to make just money off wheels and tires , they would not say "We recommend 255/45/18 or 265/40/18" . Guess they have to do that as a safety warning basically but would sell you bigger which they do, yeah they'll fit, but why would thye not recommend bigger if fits, I'm thinking yeah what happens wheel and tire fit fine, but brakes can't handle them, so just with all I read here I'll just go from 245/45 to a 255 which is bigger and if you ever take your own wheels off you know...Damn the 245/45's are big in the own respect, 255 will look good if I like 245's look.
01-29-2010, 02:30 PM
#8
Retired Mod
Join Date: Jan 2007
Location: Long Island, NY
Posts: 7,658
Norm - I don't disagree with any of your points. I even said "not optimal" but as you stated, it is a workable, less pricey way for me to have a DR on the car. For me its has worked well, I use the tires 24/7/365, not a DD, and have not experienced any issues with how they have worked. Again this is my experience, I've had this size on the car now close to three years, for me it works.
As to how it affects the OP, well DRs don't last for the life of one's car, so he yet may chose a different way to go in the future!
As to how it affects the OP, well DRs don't last for the life of one's car, so he yet may chose a different way to go in the future!