Re grinding a square tire

[sendler]

I got rid of my chicken strips today. With a grinder. And an 80 grit disc. My rear tire was starting to feel edgey from the flat spot in the center after 10,000 miles of highway commuting so I thought about grinding it round again. My coworker who is an expert body and frame tech and also a winning stock car- dirt oval driver was walking by so I asked him half jokingly if he ever ground rubber off of a tire before and he said "Only if you want to win!". It turns out that these guys buff up the tires between every heat to take the glaze off. So I borrowed his grinder and went at it with the wheel idling on the stand in first gear. No more than 15 minutes later I had a dust pan full of rubber and a nice round tire again.
.
.

.
.
.

.
.
.

.
.
.
.

[alex.s]

[alex.s]

dude.

just buy a new tire.

[sendler]

Still some good life left on that one and it transitions into lean much better now.

[Countersteer]

I can't necessarily say this is a bad idea... hmmm...

[alex.s]

Originally Posted by Countersteer

I can't necessarily say this is a bad idea... hmmm...

this is a bad idea.

[Monkeytofu]

Shouldn't be a problem unless he sanded it unevenly.

[PsHYk]

Originally Posted by alex.s

dude.

just buy a new tire.

Originally Posted by alex.s

this is a bad idea.

imma have to go with alex and say just buy a new one cus that seems like a bad idea...plus he seems to know his **** pretty good so id listen...

[jmora3]

I say you make a mold from a good tire and fill it with herculiner! Bomb proof tire! So it should never run out, but if it does then you just refill it!

[Jiggles]

Twisties? Hell naw I'm grinding my chicken strips off like an OG

[bdavison]

Ride it like you stole it, and the tire won't get flat in the middle....LOL

I usually scuff up a new tire with some 60 grit a bit before going out on a first ride to get rid of that horrendous mold release agent. But never attacked one with a grinder.

[Monkeytofu]

Originally Posted by bdavison

Ride it like you stole it, and the tire won't get flat in the middle....LOL

I usually scuff up a new tire with some 60 grit a bit before going out on a first ride to get rid of that horrendous mold release agent. But never attacked one with a grinder.

Modern tires don't use release agent like their predecessors. They do use it on the inner walls of some tires because it makes them look nice and shiny.

[choneofakind]

No release agent on new tires. I took a brand new (52 miles of straight roads actually) set of pirellis out on the track. They stuck like glue, even though I started out with GIANT chicken strips and ended with about 1/4" on each side.
Posted via Mobile Device

[sendler]

Originally Posted by bdavison

Ride it like you stole it, and the tire won't get flat in the middle....LOL

Never do. 0ver 95 mpgUS for my last three tanks in a row, 750 miles, on my CBR250R now that the warmer weather is here. Hypermiling is my form of competition.

[Chubbs032]

only heard of shaving tires for weight savings at car events

[Redgeneral]

Originally Posted by sendler

Never do. 0ver 95 mpgUS for my last three tanks in a row, 750 miles, on my CBR250R now that the warmer weather is here. Hypermiling is my form of competition.

Have you tried cornering? I hear that works pretty well. :P

Seriously though, I have +12,000km on my stock tires, they're beginning to do the same. Though mine will be replaced first thing next season to give me a little bit of piece of mind.

I've never heard of someone grinding their tires.

[sendler]

Originally Posted by Redgeneral

I've never heard of someone

I never let that stop me from trying something that I know will work well. And then sharing it on the internet.

[bdavison]

Originally Posted by Monkeytofu

Modern tires don't use release agent like their predecessors. They do use it on the inner walls of some tires because it makes them look nice and shiny.

I know they keep telling people there is no release agent....whatever.
Michelin DEFINITELY uses mold release agents. They will even tell you they do.
And they are slick as glass when brand new. You can either run 200 miles to get them scuffed in or hit it with 60grit and then go ride the snizzle out of them. Other manufacturers may not use release agent, however their tires are slick too, because they just came out of a mold that is polished smooth so the rubber don't stick. And they too need to be scuffed up before they will be worth anything.


Some of them like dunlop use chrome molds so they don't need release agents, but once they pull it out of the mold, some goober wipes it down with a silicone rag before they shrink-wrap it, and send it out to the stealership.

[edxmon]

My tires are kinda bald, you think I can dremmel some new grooves into it?

[sendler]

Originally Posted by edxmon

My tires are kinda bald, you think I can dremmel some new grooves into it?

Not the same thing at all.

[edxmon]

Originally Posted by sendler

Not the same thing at all.

I jest, I jest

[alex.s]

never had any michelins but i have taken brand new, 0 mile bt003s to the track and took one and a half warm up laps (no warmers) before going balls out with no traction issue.

if you aren't turning much and in fact get 95 mpg which i find really hard to believe unless you are going 35mph in 6th gear everywhere, why would you bother grinding useful rubber off of a tire to make it... turn in faster??? if you drive straight 99% of the time, taking away that rubber on the side is going to do nothing but make the center of the tire wear even faster.

[dubojr1]

Originally Posted by alex.s

never had any michelins but i have taken brand new, 0 mile bt003s to the track and took one and a half warm up laps (no warmers) before going balls out with no traction issue.

if you aren't turning much and in fact get 95 mpg which i find really hard to believe unless you are going 35mph in 6th gear everywhere, why would you bother grinding useful rubber off of a tire to make it... turn in faster??? if you drive straight 99% of the time, taking away that rubber on the side is going to do nothing but make the center of the tire wear even faster.

[sendler]

Originally Posted by alex.s

never had any michelins but i have taken brand new, 0 mile bt003s to the track and took one and a half warm up laps (no warmers) before going balls out with no traction issue.

if you aren't turning much and in fact get 95 mpg which i find really hard to believe unless you are going 35mph in 6th gear everywhere, why would you bother grinding useful rubber off of a tire to make it... turn in faster??? if you drive straight 99% of the time, taking away that rubber on the side is going to do nothing but make the center of the tire wear even faster.

You don't notice a rear tire getting "edgey" during cornering after it gets flat in the center? I thought everybody new that. Cornering traction of a square rear tire is reduced when you bank up onto the sharper corner that is created by the junction of the flat center to the remainder of the normal tire shape. By grinding away the higher sides, I have simply restored the normal shape of the tire that it started out life with. At the expense of some rubber that I wasn't using very often anyway.
.
My 88 mpgUS lifetime average is 3/4 highway at 68mph and 1/4 city neighborhoods. The last three tanks have been over 95 mpg since I changed to longer gearing and have started using Pulse and Glide techniques (PnG).

[dubojr1]

I'm thinking the point some of us were trying to get across was your cornering must be limited or otherwise your tire wouldn't be squaring off. I also understand your point about the "factory" shape but like Alex said, if you grind the "points" of the square you are decreasing the amount of rubber contacting the road which in turn decreases your contact patch which in turn speeds the wear on the center of the tire.

I guess in summary, the tire should last longer with no grind but would not corner as good as the factory shape.

I hope the way I've worded it makes sense...

[sendler]

Originally Posted by dubojr1

I'm thinking the point some of us were trying to get across was your cornering must be limited or otherwise your tire wouldn't be squaring off. I also understand your point about the "factory" shape but like Alex said, if you grind the "points" of the square you are decreasing the amount of rubber contacting the road which in turn decreases your contact patch which in turn speeds the wear on the center of the tire.

I guess in summary, the tire should last longer with no grind but would not corner as good as the factory shape.

I hope the way I've worded it makes sense...

I totally understand what you said but you guys are missing something. The only thing I ground away was the sides of the tire that I was not using in the first place. The center will not wear any faster because of it and I have restored the original handling.

[dubojr1]

Ok, Let's try this.

Would you agree that a tire that has, let's say 1/2" contact, would wear faster riding straight than a tire that had a contact of 1"? Being 1" of tire has more rubber to wear off than the 1/2" right?

[sendler]

Originally Posted by dubojr1

Ok, Let's try this.

Would you agree that a tire that has, let's say 1/2" contact, would wear faster riding straight than a tire that had a contact of 1"? Being 1" of tire has more rubber to wear off than the 1/2" right?

I have also restored the normal wear pattern of the tire. Nothing worse. It was dangerous to ride with the square edge and now it rides as new again.

[cbdallas]

I gotta say....I don't find this to be a horrible idea. It is kinda sickening to throw away a tire that has so much life left. As long as he ground it evenly, it shouldn't be any different than if he'd done a lot of heavy cornerning during the life of the tire.

Having said that, I'd never try it because I know I'd never get it even.

[dubojr1]

Originally Posted by cbdallas

I gotta say....I don't find this to be a horrible idea. It is kinda sickening to throw away a tire that has so much life left. As long as he ground it evenly, it shouldn't be any different than if he'd done a lot of heavy cornerning during the life of the tire.

Having said that, I'd never try it because I know I'd never get it even.

It isn't time to toss it... From the looks of the pictures he can continued ride on it for a while. His only complaint is the shape.

[sendler]

A tire balance might be a good idea now though. 11,000 miles so far and I've never balanced the tires.

[EvilPooMonkey]

if you continue to do this...just send me all of your shavings so i can save them up and make a new tire out of the unwanted shavings...we can call this process tire recycling!!!and when my new tire wears down i can shave it and send it to somebody else...rinse repeat...it'll be like the new mascot thing

[alex.s]

the square tire is not dangerous. it takes more effort to turn in, thats all. when the tire is flat in the middle, the load of the tire is spread out. if you had left the tire alone it would have lasted maybe another 1500 miles until you got to the cords in the middle. now, you will get to the cords probably closer to 1000 miles. yes, it feels weird turning in with a square tire. if you drive straight on a tire that much you shouldnt be worried about turn-in ability. if you are actually concerned with turn-in ability you would have ditched that old ass touring tire a long time ago. figure out what you actually want to do with the bike and tune the bike for that purpose. if its commuting, or, hypermiling or whatever, then its not performance based. so doing performance modifications like grinding down an already race-spent tire when you are not using it as a performance tire is a useless waste of rubber. im not trying to sound harsh but several people have tried to explain this but you seem to not be picking that up then go to talk about how you are only restoring the 'factory shape' of the tire

edit: 1500 miles is low, im thinking softer rubber ... change those to like 4000 and 3000 or something

[sendler]

Originally Posted by alex.s

the square tire is not dangerous. it takes more effort to turn in, thats all.

Nice long paragraph! I'm not sure why you are being so stubborn. The traction is poor on the square edge of a worn rear tire. The rear tire wants to slide out from under you when it gets up on that narrow edge. This is obvious and is quite common knowledge.

[Alex]

I'm not sure I'd go that far. The contact patch always flattens out when the tire leans over, so the tire is never just sitting on any edge. The increased steering effort isn't to get over the edge as much as it's to lift the whole bike off of the flat spot in the middle. I'd hesitate to say that re-rounding the profile made anything safer, but perhaps it made the steering effort more linear from straight up and down to leaned all the way over. None of it extends the life of the tire, as it is always going to be limited by the wear in the center in this type of usage.

[EvilPooMonkey]

[EsrTek]

My Sport Demons got about 3k on them and starting to square off... been wondering if I need to replace them or just go do some circles in a parking lot for 50 miles each side.... guess all I need is a rear stand and some 80 grit sandpaper... Hell while I'm at it I'll grind the sidewall so it looks like I really get that bitch really low on turns and scrape elbows!

Seriously though, I kinda get the OPs meaning and logic... grinding it down may seem as the same thing as if you actually 'corner' when turning, but I wouldn't trust my life w a modification like that!! If grinding created 1 weak spot in the tire, you won't know it until it's too late!

Buy some new tires... if I had to I would buy some Rosso 2's (I want anyway) and sell you my Sport Demons w 3k on them for the price of 1 tire!

[Kevin2109]

Why not just get new tires?.... The Stock IRC's suck ass anyway, you will be so much happier with a pair of 003/016


And the whole not riding after new tires thing is bullshit, they way the tires are taken out of the molds is different. Before there used to be a residue that was left over when popping the molds, they dont use that method anymore, you are fine. I road the **** out of new 016's after putting them on, and went right out onto the track with slicks fresh from pirelli

[sendler]

I would take all of your original take offs but the rear is the wrong size for my CBR250R. The IRC Roadwinner is an excellent commuter tire.

[sendler]

I'm up to 14,000 miles now and the square strip in the center of the original rear tire on my CBR250R needed another touch up with the grinder. 15 minutes later I had another big pile of rubber dust on the floor since I hadn't really taken it all the way the first time. Let the tire idle around on a stand and just work the square corners off with a 40 grit disc on your grinder.
.
.

.
.