Tire regroover and siper

[MChrist]

I'll post more pics later today. . now that my wife knows how to do it! (she won't tell me how, I think she's withholding information from me... keeping herself valuable!!)

 

[ed9824v]

What tires can be grooved I have some tires on the Baja Bug that my boy gave me but it this only good for big truck tires. thanks ED

 

[MChrist]

Depends on what you mean by "grooved". Cutting into existing lugs is not any problem. What takes delicacy is how deep you go into existing grooves, considered "regrooving". I only recommend regrooving steel belted tires, and then staying at least 3/32" away from the belts. That's the tricky part, since the GEOSTAR tire pictured above is out of round.

3/32" spacing is the generally accepted safe distance from steel belts, however, people I have talked to will go to 1/32" with no concern. I am not greedy, so I maintain at least 4 or 5/32" gap between steel belts and my deepest groove.

In the time it takes our tire guy to dismount and mount a new tire, I can regroove and sipe a 22. 5" tire. Cost = $1. 00 blade and one hour of my time while the truck is down for the day.

I suppose you could regroove a motorcycle tire, but I probably wouldn't. I know that racers do, since I've watched them do it... maybe I would consider adding a slight groove or two, but then that would be in the front of my mind every mile I ride. . and I prefer to pay attention to other things while riding.

You can sharpen the edges of tread blocks, and add 1/32" grooves within the blocks if you wanted to.

 

[MChrist]

What is SIPING and how does it help your tires grip the road - YouTube

The benefits of siping your tires. The less aggressive the tire, the more noticeable the difference.

 

[Barry]

I did something STUPID!



I loaded a new blade in my re-groover tool and went to work only to discover I went too deep and exposed the steel cords... ... ... ..... now I have a practice tire... ... ... ..... but at the expense of ruining one of my good Continentals.



Oh well... ... ... ... ... ..... practice makes perfect!

 

[MChrist]

Oh, no!! Yep, you have to measure, measure, measure... then err on the modest side. 3/32" is the amount of rubber you want to leave on the carcass. Knowing where that 3/32" limit is, is the tricky part. You have to cut, measure, cut, measure again until you know how much to remove. So far, removing 4/32" from a Michelin XZE leaves you with at least 4/32" "undertread", a very safe amount.

Luckily, yesterday I was playing with my groover on my scrap tire, (coming up with different designs) and I cut down to just above the cords. I thought about vulcanizing the groove back in, so I took my rubber cement from a tire plug kit, and "glued" it back in. I will go back to work today and see how tough it is to pull out. If it is successful, I will cut it again at a more shallow depth. If that works, that may be an answer to your problem. I'll let you know later today. (Before anybody freaks out and says it isn't safe, it's just an experiment for now... )

So... how deep did you go? Since I haven't worked on my Continentals yet, I'll be interested if there is as much undertread as the Michelin. I think on a different thread, I mentioned going 2/32" and measuring the safety margin with a pick or an awl. And measure at different spots around the tire in case the tire is out of round, like that GEOSTAR I have as one of my practice tires.

Online, you can buy used Continentals for around $130 delivered, so it's not the end of the world. I just had a new HSR installed in October, and the tire was $336, plus all the extras=$425 out the door. This was Load Range G.

At least you have a practice tire now!!

 

[Barry]

Well fortunately, I only paid $120 for 4 TO Continentals. I cut half way around the tire so I don't think I can glue it back in. I think I saw 4 Connies on Ebay like mine for $200... ... ..... somewhere up your way.



My plan is to groove two tires... ... ... ... successfully... ... ..... and then have them mounted, trued and balanced.

 

[MChrist]

I'm starting to look for used tires that I can regroove in the 225/70/19. 5 size. Getting them cheap and fixing them up can save me thousands a year!!

Keep that strip of rubber, I'll let you know how the vulcanizing went later today. I figure if I can't pull it out, and I can lift the tire from that point, it might be good...

So, how deep did you go?

 

[Barry]

Well, they are in Tennessee. Thought they were closer to you.

I have been checking Ebay under parts for 19. 5 tires... ... .....

 

[MChrist]

I saw the 4 on eBay. Pick up only and in Oklahoma... but a great price for 4 tires with tons of tread left!!! Around here, they would go for $200 apiece, used.

 

[MChrist]

Barry, I tried the rubber cement trick on a rubber strip that I removed. No go. I know that particular tube is older, but I pulled the strip right out. I thought it was supposed to be a vulcanizing agent... I cut another strip and tried to reattach it with black RTV. I'll see if that does anything...

 

[Barry]

Think of the centrifugal force at 60 mph!

 

[MChrist]

I've thought about it, just haven't done the math. Once glued, it would be trimmed so only a few 32nds would be there. It's more to keep salt and water off the steel belts than anything.

How's your project coming?

 

[MChrist]

Barry, I'd like to know how deep you cut so I will know when it comes time to do my Continentals. As far as re-attaching the strips, the rubber cement didn't hold well at all, but the black RTV held quite well.

Since I'm talking about regluing a strip back in, and then trimming it back to the proper depth, the rubber strip would only be 3/32" inch thick. . about the thickness of 2strips of rubber band material. Again, it's only there for corrosion resistance for the steel belts, not strength. You could also just put a thin layer of RTV where you cut too deep. It's up to you.

Any progress/pics?

 

[Barry]

Got busy for the last few days and have not had time to work on it.



I foolishly set the blade at the deepest cut. When the blade got dull, it broke. I will install a new blade and give you the measurement. I will then back off about 1/8th inch.

 

[MChrist]

Barry, you may want to re read the first paragraph of link #46. Ya big dork!!

I'm not sure why your blades are getting dull and breaking. I can do (4) 22. 5" drive tires with one blade, as long as I'm looking out for stones in the tread.

Practice when you have time, you'll get the hang of it. I've successfully worked on over 20 tires now, with great results, improved traction, and no problems at all, like chunking, separation, etc.

Now that I've looked at our tire costs, I noticed that the cost to purchase a tire has skyrocketed. Last year (January) a Continental HSR 225/70/19. 5 LRG was $276, in October, the same tire was $336. Add in labor, valve stems, etc. and the tire shop bill was around $425 for one tire. Add in our driver time, waiting, etc...

I had several tires that had legal amount of tread just before winter that I would have swapped for new tires. Then, I would pay disposal costs for the old tires, because it wasn't worth paying to have them reinstalled. Now, I regroove them and not only will I have all the traction I need for winter, I will have traction for the wet, muddy Spring, and probably most of the year.
We can get retreads for our 19. 5s from our local tire shop, but they don't give credit for your old casing, whether or not your casing is good... so I don't worry about them saying "nope, can't use them, you regrooved them too deep". So that's not a concern.

My modest calculations indicate I will save $6,000-$9,000 on tire costs this year. Add in the extra safety from not sliding to a stop and possibly rear-ending somebody...