Tire Size on a 700c

I’m trying to build up a 700c uni but I am undecided as to which type of wheel to make. Of course there is the classic 29er wheel with Big Apple or Nanoraptor, but I have been thinking about building it up with a road rim and tire for minimal rolling resistance. Anyone have any experience with this type of uni? Let me know what you thought.

i work ina bike shop and the tire we ussually equip for our 700c road rims are between 700x38c and 700x42c they are relatively thick like 1.5 inches or so and thet seem to be smooth but but not race bike smooth, they doo have some bite to them.

Peter bier tried this and it didn’t work at all, highly not recommended

yes but mike fule also does this and has had great sucess


I’m looking to do the same thing. I have the tire and hub but didnt deside on the rim yet. I got the maxxis overdrive tire. Mostly I dont have money so once I do I’ll be riding. Oh and I think I’m building the frame in shop soon.

Make me one?

That could happen. Some money will be invovled but not a lot. I’ll start on the bearing caps next week. Do you know how long the legs should be? About 15 inches? I’ll be machining it to the size of a UDC hub. I’m guessing thats what you’re going for.

what in the world do these bikes look like? most road bikes from our shop use 700x23 tubes, some use 700x25, touring bikes take 28 or 32 and hybrids take 38+. a few crazies even run 700x18.

obie- i’d try something fatter. maybe a 28 if you still want it to look like a skinny road tire/wheel.

I’ve been riding on a skinny road tire for 4 years, and have no significant complaints. Definately rolls up VA hills nicely, manuvers well, and has earned the respect of the urban bike snobs with its track bike “look”. I’ve done two MS-150’s with it, averaging between 9-11 mph. Top speed is 17.2 mph (right before a nasty upd). One complaint is tube poppage on scattered gravel or other small road debris. This was a constant annoyance early on, but since getting a thorn-resistent tube I haven’t had any problems (last two years or so). Pic from last MS-150 ride.

edit: I may be interested in selling it in the near future (I have to use my $100 Coker gift certificate from the Rolling Trials Comp). If you’re interested Obie, PM me or wait for my thread in the trading post.

Re: Tire Size on a 700c

On Wed, 26 Apr 2006 17:54:12 -0500, TheObieOne3226 wrote:

>Of course there is the classic 29er wheel with Big Apple
>or Nanoraptor, but I have been thinking about building it up with a
>road rim and tire for minimal rolling resistance.

Actually (and surprisingly for many people), a fat tyre has LESS
rolling resistance than a narrow tyre, everything else being equal.
Same tyre pressure, same tread, same rubber thickness, same riding
surface etc.

that was my expiriance when i built up a 700c wheel with a thin Continintal road tyre,

i was hoping for the smooth rolling effect but since you have to have 120 PSI in the tyre to keep from pinch flating it was like the princess and the pea, i felt every bump and it was acually slower that the 29er NAnorapter uni i sold to build it :angry:

the skinny wheel is very smooth on a gym floor but outside those ideal conditions a fatter 2.1 is faster since you can maintain a better cadence because the air volume is minimalizing surface ir-regular-itties (sp?)

bottom line…the skinny looks sheak but acually goes slower than a fatter 29er tyre because of rolling resistance…

I’ve tried 28mm, 35mm, 45mm and the big big apple (65mm?).

I’d never go back, the big apple is best by far.


That’s only true in theory - the important part is “same tyre pressure”. If you’re running a wide tyre at the same pressure as a narrow tyre then it’s way too hard. From what I’ve heard, people run Big Apples at 60psi or so, and consider that hard. A normal 700c road tyre like a 28mm or 25mm would have to be run at 100psi or more. With tyres set at a suitable pressure for their width, the wide one will have a slightly higher rolling resistance.
I suspect the reason wide tyres are better on unicycles is that they are more forgiving and lead to a smoother ride (because the pressure is lower). So less energy is used correcting the trip-ups.


I thought I remembered seeing you on a thin wheeled 700c uni in some article you posted on here, Frank. I figured it would perform well despite the opinions of several people who have never tried it that believe otherwise. I’m glad to hear someone has had good experiences on a road wheel. What rim do you use and what tires have you tried?

I’ll definitely check out your for-sale thread whenever you make it. However one of the reasons I was considering using a common road tire and rim is because I can get them locally and quite possible for free. I am trying to build up the cheapest possible rig that can get me through the 8th annual LBI Unithon (which I’m expecting Raphael or Roe Sprouls to post about any day now). I have a hub and I think I may be able to borrow Shadowuni’s KH29 frame so all I need is a rim and tire.

18 is by no means “crazy” on a bike. Anyways I was thinking about something in the 23-25 range. The thing is though, I can always change the tire later since I can get them for free usually.

18 is getting significantly less common. even serious riders usually reserve that for race day. plus i think that’d be murder on a uni. but you could try it. 25 would probably be alright.

Physics says you are wrong. A larger contact patch (with the ground and with the air) produces more friction and more resistance.

Klaas always brings this up when we talk about tire pressure, and he doesn’t seem to listen when I point out that he is correct only if the tire pressure is the same. You can run a 700x25 at 120psi, while a Big Apple would become a bomb at that pressure (if you could even get it there). I think it’s probably true that a Big Apple at 60psi has less rolling resistance than a 700x25 at 60psi, but that’s not a meaningful comparison.

Exactly. A flat road tire has more rolling resistance than a fatter tire that is fully inflated. Inflated to proper pressures though, the road tire wins by far.

On my road bike I run my tires at about 160 psi (rated to 110) and the contact patch is less a patch than a point on the ground, and there is almost no drag generated by the wheel.

ok dude, you sound dead set on your mission to get a rig going with a skinny road tyre so why ask for advice if your not going to listen to it…?

i have built and rode a uni before with a 700x28 and outside of a gym floor it was a total peice of crap when it comes to rolling resistance…


its totaly differant in the worst way, even the smallest crack in the sidewalk will slow you down…on a road bike you have two freakin wheels and a ton of gears to power of that stuff not to mention your weight is not all on one wheel.

your going to find out the hard way that there is a point where bike knowledge doesnt apply…if it did then the skinny airless tyres that are on those pre-Coker uni’s would be all the rage.

fortunatly your making this cheap…get a frame that has clearance for a 29er tyre and a rim wide enough to take since you will be moving that way after you ride your new rusty razor.