Shimano RS80-C24 and high pressure tyres (145psi)

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Shimano RS80-C24 and high pressure tyres (145psi)

Postby mgdavid » Fri Sep 02, 2011 1:53 pm

Gday folks, newbie here, not just to the forum but also to the wonderful world of cycling.
A quick intro, I just started cycling again about 2 months ago (after hybernating for 15yrs), and I've been a passive spectator jumping around forums to find answers to my questions or just to broaden my views in general until today I decided to join because I'm stuck (very limited people around to ask questions).

OK here we go, 2 weeks ago I bought a new set of wheel - Shimano RS80 C24, Vredestein Fortezza Superlite tyres, and Vittoria Ultralite tubes.
The Vredestein tyres have a recommendation of 145psi (min 115psi - max 170psi). And from Shimano website, the only thing I found about tyre pressure recommendation is "The tires should be inflated to a suitable pressure before use". At the moment I have my tyres set up at 140psi (front and rear).

I went to my LBS, and they said as long as I've a good set of rim tapes which can withstand high pressure then that should be fine. But other mechanics at different stores recommended me to check the pressure limitation for the RS80 because every wheels have different standards.
I'm just concerned that if the RS80 can't withstand high pressure tyre, then I will be risking my butt if the tyres suddenly come off.

FYI I weigh approx 80kg.
Currently I use the wheelset and tyres for general use around 20km everyday and some 50+km on weekends and always try to avoid potholes or debris.

Apologies for my low knowledge in this topic. Thanks.
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by BNA » Fri Sep 02, 2011 7:52 pm

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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby MREJ » Fri Sep 02, 2011 7:52 pm

That seems very high pressure for someone your weight! You might like to check the tyre manufacturer's recommendations. I weigh 73kg and run 110/105 on good roads, less on rough roads. There is a fair bit of information to suggest that really high pressure is not faster except on extremely smooth surfaces (e.g. indoors) as all the little bounces (that you might not even notice) dissipate your energy. It's also more uncomfortable, which apart from being unpleasant, probably also erodes your energy over time.

Re the wheels, the Shimano website might help.
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby mgdavid » Fri Sep 02, 2011 9:36 pm

MREJ wrote:That seems very high pressure for someone your weight! You might like to check the tyre manufacturer's recommendations. I weigh 73kg and run 110/105 on good roads, less on rough roads. There is a fair bit of information to suggest that really high pressure is not faster except on extremely smooth surfaces (e.g. indoors) as all the little bounces (that you might not even notice) dissipate your energy. It's also more uncomfortable, which apart from being unpleasant, probably also erodes your energy over time.

Re the wheels, the Shimano website might help.


Thanks MREJ! Agree with you, I have a feeling that these tyres are more suitable for racing on smooth surfaces as they perform better at high pressure. No racer here, so I guess I'm swapping back to my conti just to be on the safe side.

And regarding the shimano wheels, the quote I mentioned before "The tires should be inflated to a suitable pressure before use" was taken from shimano website. Shouldn't be a problem anymore now.

Looking forward to weekend. Safe ride!! :D :D
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby toppity » Sat Sep 03, 2011 8:48 am

I have a set of the RS80's and have run tri comps on them (assume they are similar to the V-steins you are running). Never had them over 120psi though. No science to this, just experience. I weigh 100kg and have done o.k. in a few races with this setup so I'm o.k. with it.
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby mgdavid » Sun Sep 04, 2011 1:13 am

toppity wrote:I have a set of the RS80's and have run tri comps on them (assume they are similar to the V-steins you are running). Never had them over 120psi though. No science to this, just experience. I weigh 100kg and have done o.k. in a few races with this setup so I'm o.k. with it.


Yea mate, i did some more searching and yes these vredestein superlites are ideal for crits and TT. I dont think it's a good idea to use them for long distance rides on average road with 145psi tyre pressure recommendation. Anyway these RS80 are great, love them.
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby jacks1071 » Thu Sep 08, 2011 1:22 pm

mgdavid wrote:Gday folks, newbie here, not just to the forum but also to the wonderful world of cycling.
A quick intro, I just started cycling again about 2 months ago (after hybernating for 15yrs), and I've been a passive spectator jumping around forums to find answers to my questions or just to broaden my views in general until today I decided to join because I'm stuck (very limited people around to ask questions).

OK here we go, 2 weeks ago I bought a new set of wheel - Shimano RS80 C24, Vredestein Fortezza Superlite tyres, and Vittoria Ultralite tubes.
The Vredestein tyres have a recommendation of 145psi (min 115psi - max 170psi). And from Shimano website, the only thing I found about tyre pressure recommendation is "The tires should be inflated to a suitable pressure before use". At the moment I have my tyres set up at 140psi (front and rear).

I went to my LBS, and they said as long as I've a good set of rim tapes which can withstand high pressure then that should be fine. But other mechanics at different stores recommended me to check the pressure limitation for the RS80 because every wheels have different standards.
I'm just concerned that if the RS80 can't withstand high pressure tyre, then I will be risking my butt if the tyres suddenly come off.

FYI I weigh approx 80kg.
Currently I use the wheelset and tyres for general use around 20km everyday and some 50+km on weekends and always try to avoid potholes or debris.

Apologies for my low knowledge in this topic. Thanks.


Thats way too much pressure mate - the most you should run for your weight is 120psi. I would try 115 front and 120 rear for racing as your maximum's, and I would test using less.

At 145psi you are asking for punctures, your tyres will wear quick and the ride is going to be rough as anything and you would be putting extra stress on the rim as well. High pressure also equals less grip, and hit a bump and your back wheel is in the air - something you don't want in a crit.

I have a buddy who works at Vredestein, the reason they allow such high PSI ratings is for marketing purposes. I guess they figure some people buy tyres based on their maximum PSI ratings which maybe true?
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby mgdavid » Thu Sep 08, 2011 3:25 pm

jacks1071 wrote:Thats way too much pressure mate - the most you should run for your weight is 120psi. I would try 115 front and 120 rear for racing as your maximum's, and I would test using less.

At 145psi you are asking for punctures, your tyres will wear quick and the ride is going to be rough as anything and you would be putting extra stress on the rim as well. High pressure also equals less grip, and hit a bump and your back wheel is in the air - something you don't want in a crit.

I have a buddy who works at Vredestein, the reason they allow such high PSI ratings is for marketing purposes. I guess they figure some people buy tyres based on their maximum PSI ratings which maybe true?


Hi mate, 9 out of 10 people I spoke to had the same opinions as yours.
The ride is indeed very rough on general road, but on a smoth road the tyres roll at their best - fast. The reason I bought these vreds was because they are very light and have very low rolling resistance, which are true.
So I guess these vreds will be sitting in my garage collecting dust.
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby Mort » Thu Dec 29, 2011 9:26 am

DO NOT USE Vredestein Fortezza Superlite tires on the Shimano RS80 C24 wheel! When I did so, the front tire bead popped off the rim going downhill over some expansion bumps. A header into the pavement is always ugly. I still feel it in my neck two months later. I've never lost a tire bead off a rim in 30 years of riding. The bead is too loose for this rim. Another wheel manufacturer recommended never using Vredestein tires on their rims some years ago for this reason. Apparently, this tire cannot be ridden safely at normal tire pressures. It must be a race day only tire for smooth roads.
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby jules21 » Sat Dec 31, 2011 12:03 pm

Mort wrote:DO NOT USE Vredestein Fortezza Superlite tires on the Shimano RS80 C24 wheel! When I did so, the front tire bead popped off the rim going downhill over some expansion bumps. .

what pressure were you running them at? i can understand that if you were running below the recommended minimum, they might come off. still, that's worrying.
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby sumgy » Sat Dec 31, 2011 12:31 pm

Dont know about the suitability of the tyres to the wheels or anything else but at 80kg I cannot see that you need 140psi in your tyres.
I weight a couple of kg more and never go above 115psi even when racing.
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby brawlo » Sun Jan 01, 2012 10:13 am

Definitely too high on pressure. I tip the scales around 115 and run 120psi for racing. Partly due to the fact I run Contis and that's their max, but on the road I wouldn't run more. Training/cruising, I run 100F/110R. I also race track and run my rear at 140psi.
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Re: Shimano RS80-C24 and high pressure tyres (145psi)

Postby rkelsen » Sun Jan 01, 2012 10:15 am

Outside of racing, nobody needs more than 100psi.
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