# Tire pressures and widths?



## bme107 (Jul 23, 2008)

First off I've got 700D wheels(frame) so any suggestions of, "go 26/29/tubeless/ghetto-tubeless..." will be wasted. I will be putting 650b tires on and running tubes.

I'm interested in what pressures you are riding and what widths your tires are. If you have any experiences with a cross-over or city tandem that would be appreciated too. Team plus bike weight would be good to know as well.

Over the weekend my brother and I took the tandem out for a casual shake down on the road. We are 170lbs+170lbs+48lbs and were riding 1.4" "GT Crossover tires" at the max 60psi. The front was noticeably squished and the rear was alarmingly so. I'd be leery of taking these tires on a crushed stone rails to trails type path in this condition. Hopping down a curb or hitting a pothole would have definitely flatted them.

I'm trying to sort what combination of tires, widths and psi will suit us. Hoping for something about 2" if possible.


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## clj2289 (Jan 2, 2010)

*wow, that is a very difficult question to answer*

You may be the first person in the world to run this particular configuration of 650x2in tires. I do not have any 650 wheeled bikes, so I do not know. The wife and I are about 270 lbs total body weight, bike and total gear (tools water etc) ~60 lbs and we ride a 29er tandem (29x2.3), typically in the low 30s psi. I have found the higher the volume the tire, generally the lower pressure. If we are on rocky trails I will put up to 35 psi, but I have never gone higher.

I think you could start at 35 psi on 650x2.0 and see how it handles. You could bring a pump and an air gauge with you and adjust as needed. You will also need to bring a couple of extra-extra tube incase the pressure is too low and you get a pinch flat.

Speaking of tubes, make sure you get the right size tube for the tire, width matters...


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## dir-T (Jan 20, 2004)

clj2289 said:


> You...(29x2.3), typically in the low 30s psi.
> 
> 
> > Wow, that low eh? Do you have problems with pinch flats on rough terrain or do you feel sluggish on pavement?
> ...


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## thadthetroll (Jan 22, 2004)

*Ours*

We are on a 26er with 2.35 Nevegal in the front with a DJ2 shock and a 2.1 Nevegal in the back. Front is 35psi,rear @ 40 no flat issues. We typically ride as gnarly singletrack as we can navigate and are doing more as our skills improve.
We are about 340# total weight bike/gear and us and have no issues with flatting. We use tubes and ride in the Western NC area..Pisgah,Dupont,Bent Creek, Grandfather District


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## bme107 (Jul 23, 2008)

There are a few of us on here that have vintage GT Quatrefoils with this odd wheel size. One guy runs the NOS 2.0 tires meant for these rims and he and his wife run the bike very casually (probably like I'll use mine). Another guy is going to run 650b x2.35 but the bike is not complete yet (sounds like he intends more off-road MTB-ing than we do). I'm not sure what the 4th guy runs.

Thank you for all the input. Estimating the longitudinal contact patch of the tires I've roughly calculated the load that the tires can carry. Your team weights are within the tire capacities found in my crude calcs. Using the same methodology on my current setup we were 10% overloaded.

I was worried that I was going to need a tire that went to a much higher psi than the current 60psi in order to survive. Seems that a reasonable 2.0 or greater width at a psi in the mid-high 40s should work. All within max recommended pressures of typical stock tires.


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## Plum (Sep 14, 2004)

bme107 said:


> Another guy is going to run 650b x2.35 but the bike is not complete yet (sounds like he intends more off-road MTB-ing than we do).


Yeah, haven't actually had the opportunity to ride the bike yet, but it looks *****en leaning against the wall in the basement..

Hopefully this fall..

Plum


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## clj2289 (Jan 2, 2010)

Knock on wood, we have not had any problems at 30 PSI. I have a feeling that folks could run a lower pressure. We also have a very nice suspension fork, that may be a part of the reason that we are not experiencing pinch flats.


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## muddybuddy (Jan 31, 2007)

I've been running the 2.3s on my Quatrefoil for a few months now. Although I love the size, the wheel has to be almost perfectly true in order to get through the U-brake on the rear. With a disc conversion, I don't see there being any clearance problems. I have a 2.1 on order for the rear just to avoid contact though. I'm at 195lbs and my stoker is between 65 and 95lbs depending on which one is back there. Tire pressure is typically 35-50psi, a little higher on the road.


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## bme107 (Jul 23, 2008)

muddybuddy said:


> I've been running the 2.3s on my Quatrefoil for a few months now. Although I love the size, the wheel has to be almost perfectly true in order to get through the U-brake on the rear. With a disc conversion, I don't see there being any clearance problems. I have a 2.1 on order for the rear just to avoid contact though. I'm at 195lbs and my stoker is between 65 and 95lbs depending on which one is back there. Tire pressure is typically 35-50psi, a little higher on the road.


Thanks. You were the "unknown" other owner mentioned above.

I hadn't considered clearance problems with the U-brake yet. Have you tried airing it down a bit to fit through and then topping it off once the wheel is seated in the drop outs?

Overall it sounds like my test ride was one of the more heavily loaded and included the smallest tires among people here. (road tires and pressures excluded) Typically my stoker and I will be about 40lb less.


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## muddybuddy (Jan 31, 2007)

The problem wasn't getting it in, its just there was very little clearance between the "U" of the brake and the outtermost knobs on the tire. It fits as long as the wheel it true, but once there was any side movement it was rubbing.

My bike also came with the 1.4 tires, and I wouldn't recommend them for anything other that road use and maybe groomed dirt roads.


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## bme107 (Jul 23, 2008)

Good to know. That settles it then, 2.1" is the way I'm going.


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