Bridgestone Potenza RE-71R 305/30R-19 (new size) Discussion Thread

[fzss]

Originally Posted by RKeeton

I had the 305/30/19 RE-71R tires mounted today. Big issue getting them to fit on the 10in rims but they finally seated. The camber went from 2.2 degrees to 1.9 degrees on the front from the 285/35/19 RE-71R tires previously mounted. They definitely are much wider. I will have more information after tomorrow on how they handle. It's all good!.

Picture of the fitment?

[Cornercarver]

Originally Posted by RKeeton

I had the 305/30/19 RE-71R tires mounted today. Big issue getting them to fit on the 10in rims but they finally seated. The camber went from 2.2 degrees to 1.9 degrees on the front from the 285/35/19 RE-71R tires previously mounted. They definitely are much wider. I will have more information after tomorrow on how they handle. It's all good!.

Why did the camber value change? Did you redo the alignment or was the tire too close to the strut? Your alignment shouldn't change due to a tire change, they shouldn't be related...

[ICTsccaCamaro]

Originally Posted by RKeeton

I had the 305/30/19 RE-71R tires mounted today. Big issue getting them to fit on the 10in rims but they finally seated. The camber went from 2.2 degrees to 1.9 degrees on the front from the 285/35/19 RE-71R tires previously mounted. They definitely are much wider. I will have more information after tomorrow on how they handle. It's all good!.

Also would like to know how close the 305 is to the front strut?

[L99CAMA2011]

Why are we putting 305s on a 10" wide rim?

[JusticePete]

Originally Posted by L99CAMA2011

Why are we putting 305s on a 10" wide rim?

10.5 is the minimum mfg spec rim width.

[ICTsccaCamaro]

Originally Posted by L99CAMA2011

Why are we putting 305s on a 10" wide rim?

GRIPPPP!!! And the fact we can't change wheel width in street class, SCCA rules make us due some less than conventional things to turn fast but the 305 on a 10" isn't to bad, I recently mounted a set of 305 BFG rival S's on the front of a buddy's viper with 10" wide front wheels it was actually just a slight bit of tire pinch, he went out the next event and went FTD so I dont think the tire pinch "hurt" his performance to bad.

[JusticePete]

Originally Posted by ICTsccaCamaro

GRIPPPP!!! but the 305 on a 10" isn't to bad, I recently mounted a set of 305 BFG rival S's on the front of a buddy's viper with 10" wide front wheels it was actually just a slight bit of tire pinch, he went out the next event and went FTD so I dont think the tire pinch "hurt" his performance to bad.

It isn't about performance. It is about safety. A tire mounted on a rim below MFG spec is more likely to sustain side wall damage hitting a bump or a pot hole. Undetected side wall damage on a car used on a road courses could results in horrendous carnage. Here is a list of priorities in my shop:

1. Driver Safety
2. Driver Safety
3. Driver Safety
4. Driver Safety
5. Driver Safety
6. Driver Safety
7. Driver Safety
8. Driver Safety
9. Driver Safety
10. Fast Car

We would not let a car with a 305 on a 10" rim leave the shop.

[L99CAMA2011]

Originally Posted by ICTsccaCamaro

GRIPPPP!!! And the fact we can't change wheel width in street class, SCCA rules make us due some less than conventional things to turn fast but the 305 on a 10" isn't to bad, I recently mounted a set of 305 BFG rival S's on the front of a buddy's viper with 10" wide front wheels it was actually just a slight bit of tire pinch, he went out the next event and went FTD so I dont think the tire pinch "hurt" his performance to bad.

Grip????? By reducing the contact patch on a pinched rim resulting in less real estate in the contact patch department. How is that grip. I tried many wheel/tire options. I noticed more grip with the wider rim no question. There is also the ability to support the weight. My current wheels setup now is way more supportive in the front end with the 305s on 10.5" rims than on the 10" I had in the past. I intend to put 11s on the front when I get funds for front hubs with track studs and 10mm spacers with hub centric mounting. Or CCW/Weld rims with the right offset. On a 10" rim and too wide of a tire you will experience way too much tire slop during quick direction change maneuvers.

[ICTsccaCamaro]

Originally Posted by JusticePete

It isn't about performance. It is about safety. A tire mounted on a rim below MFG spec is more likely to sustain side wall damage hitting a bump or a pot hole. Undetected side wall damage on a car used on a road courses could results in horrendous carnage. Here is a list of priorities in my shop:

1. Driver Safety
2. Driver Safety
3. Driver Safety
4. Driver Safety
5. Driver Safety
6. Driver Safety
7. Driver Safety
8. Driver Safety
9. Driver Safety
10. Fast Car

We would not let a car with a 305 on a 10" rim leave the shop.

Most of our autoX courses are pothole free and the wheel and tire set up is autoX only no road course

[RKeeton]

My impressions of the tire yesterday were mostly positive. The course was a small asphalt lot. The course design had some of the features of a Nationals course on a smaller scale of course. The car transitioned very well in the slaloms and on the faster sections changed directions easily. There was no tendency to oversteer when accelerating out of slow corners. I was getting understeer in the sweepers if I applied throttle too soon but it wasn't a grippy surface at all. We are playing with tire pressure to control that. Air temperature were close to 100 degrees. My co-driver placed 3rd in the PAX and I was 6th. We are looking forward to the concrete at Lincoln.
I will take a picture of the car with the tires as soon as I remove the cone marks. :^)

[RKeeton]

Originally Posted by ICTsccaCamaro

Also would like to know how close the 305 is to the front strut?

The tire is close to the strut but I did back off on the camber to make sure there was no contact. I could get my fingers in between the two on both sides. I will add more camber if possible.

[JusticePete]

Originally Posted by RKeeton

The tire is close to the strut but I did back off on the camber to make sure there was no contact. I could get my fingers in between the two on both sides. I will add more camber if possible.

It is possible. Get an ordinary #2 lead pencil. If the pencil can pass you are good to go.

[ICTsccaCamaro]

Originally Posted by RKeeton

My impressions of the tire yesterday were mostly positive. The course was a small asphalt lot. The course design had some of the features of a Nationals course on a smaller scale of course. The car transitioned very well in the slaloms and on the faster sections changed directions easily. There was no tendency to oversteer when accelerating out of slow corners. I was getting understeer in the sweepers if I applied throttle too soon but it wasn't a grippy surface at all. We are playing with tire pressure to control that. Air temperature were close to 100 degrees. My co-driver placed 3rd in the PAX and I was 6th. We are looking forward to the concrete at Lincoln.
I will take a picture of the car with the tires as soon as I remove the cone marks. :^)

Very cool I try to take a look at Nationals you running FS or CAM?

[RKeeton]

Originally Posted by ICTsccaCamaro

Very cool I try to take a look at Nationals you running FS or CAM?

F Street, We will running on Thursday/Friday. Might be the only yellow car in grid.
Here is a picture in between thunderstorms here today.