Tire size for a more comfortable ride on HORRIBLE roads?
 

I live in the Northeast and the roads just blow. I sometimes, but not often, have gravel roads too. I have a 700c rim and was wondering what size tire may make for a better ride if I am not super concerned with speed? I have an OLD Mangusta 5000 I put a few components on. I was looking at 700 x 32. If they fit, would that work?

The main limiting factor is going to be the frame and brakes, not the rims. There are some advantages to using wider rims with wider tires, but it's not a very hard requirement. Back in the early days of MTB, there were people running 2" tires on rims with ~17mm internal width, and it was kind of silly but it worked.

Since you have the bike in hand, you are going to be the best source for finding out your frame's tire clearances. Check how much clearance there is around your current tires: around the tires in the brakes, around the front tire in the fork crown, next to the rear tire at each chainstay, and above the rear tire at the chainstay bridge (if it exists) and the seatstay bridge.
For each 2mm in added tire width, the tire will get 1mm wider to each side, and may also get around 2mm taller. It's good to leave a few millimeters of spare clearance for safety.

Keep in mind also that there's a bit of variation between tire models in stated versus actual inflated size. And that rim width affects how wide a tire inflates: narrower rims tend to result in tires inflating to a narrower actual size.


If you're uncomfortable using a low enough pressure with your current tires to ensure a smooth ride, going wider might actually speed you up. When you're getting vibrated by the road surface, the energy used to do that vibration is being stolen from your forward momentum. When you combat this by pumping a tire squishier, it does result in more energy lost from tire deformation, but since it also reduces the amount of vertical deflection being carried through to the bicycle and rider, it can actually make the overall system roll more efficiently.

This sort of consideration is relevant even on extremely smooth roads. In a test by Silca, even an plush smoothly-rolled asphalt surface, a 190lb bike+rider on 25mm tires got slower when the tires were pumped above ~110PSI.

The style of road tire has a big impact on performance, though. Of particular note is that tougher tires tend to have inferior rolling performance: a 32mm GP5000 is going to run circles around a 32mm Marathon Plus, for example.

What width and PSI are you running now? What’s your weight?

You probably could do ok with 28mm and drop PSI to 65-70F, 70-75R unless you are over 200 lbs.

Those were cool looking bikes:thumb: I doubt you can get a 32 on it. Measure and go with the largest that will fit, even if different sizes front and rear.

700 x 28c at 80psi works good in gravel roads here

Thanks. I am 165 running 23 x700 at 110 psi

I also wasn't sure if you could safely ride 28 at those psi's. I understand they are more prone to pinch flat since I am not tubeless.

Appreciate your time.

Thanks for the advice

Much appreciated! That has to be an improvement from 23 at 110 psi

How are the roads near you?

It is not bad looking, I might want to paint it. Nice summer project.

i also live in the northeast and feel your pain. I have 32mm GP5000 and they are great.

Thanks a lot! What psi may I ask?

I use 700x32 GP5000’s on one of my bikes that I ride at 90 psi and they ride very comfortably.

For a start, drop your current tires to 80F and 90R. Do it now and thank me later.

My next ride, done. I'll thank ya now.

Yeah. At 165#, you were riding on tirres that were way too hard for no reason.

So lowering your tire pressure os the first step. Then get wider tires. Most any bike should be able to take 28s, but yet wider could be better.

In my experience I have found those pressures ok with 23's, but only if you are confident on avoiding pot holes, sharp bumps, rocks etc.
In other words I will only use those pressures when riding solo or small groups.
With larger bunch rides and races I go higher as the likelihood of not seeing obstacles increases, plus combined with the greater desire to avoid a pinch flat.

Try latex tubes too. I switched a few weeks ago. Big difference on chipseal and rough roads with Conti GP Classics (700x25) on my old steel road bike. My neck is screwed up from being hit by cars, twice, and 700x25 is the widest my bike can handle. Lower pressure helped. Latex tubes helped even more.

I rode home on 23mm and 25mm tires at 60-ish psi after fixing flats with a mini pump, and it was very smooth over broken up roads and I had no issues (except it feels wonky uphill when your weight is on the rear wheel, and I was gentle going speed bumps and avoiding potholes). While I wouldn't go so low intentionally, 110 psi is really overkill; my "go to" pressure over nice roads is about 95 psi, where the front is a 23mm and rear is a 25mm and I weigh 72kg / 159 lbs.

If I'm going to do a ride on bad roads, I'll go down to about 85 psi, and actually not only it feels noticeably more "muted" over the rough stuff, I set a few PBs and the odd KOM on crappier roads that way. Adjusting tire pressure would be my first port of call.

I too am 165 lbs. (approx.187 with bike, tools, spare tubes, bottles) and have rapidly declining, very uncomfortable road conditions these past few years. On a road repaved in 2016 there are already numerous potholes, surface wrinkling, surface breaking up into little tiles that can be heard rattling when passing over them which are soon to be more potholes. With state flat broke due to Covid there won't be any secondary road repair in the near future. I recently switched from 700x23 Gatorskins front and rear to 700x25 on front and 700x28 on rear and have ridden several months at 63 psi front/83 psi rear with no flats. I may be able to squeeze in a 28 on front if conditions worsen. Bike still seems fast enough, I was surprised by that. When doing a standing climb the front tire does very visibly deflect but no pinch flats yet. I have had some (but not dramatic) increase in comfort. So this has kinda worked for me but am very sad to say that even 25s will not fit on my 1990s Bianchi or Basso, so will I ever ride them again?

Very helpful, thanks.-

Didn't know that was a thing. Thanks.

Thanks

+ 1 on this. Interesting bike but I doubt the OP can get a 32c on the bike:

https://www.bikeforums.net/classic-v...105-group.html

Might not be a bad time for N + 1 (another bike) if looking to ride gravel. Supply and demand will make that tougher though because of the pandemic.

"Interesting" indeed lol. I took that biopace crank off. It was awful.

I have not measured it yet, every time I go down to measure something distracts me or comes up. I also have to make sure the brakes go around it too. May try for 28's