700D tires for my Continum
Hi folks, I am new here and I need tires for my GT Continum. 700D size. I have been reading online that this size is no longer available but I won't
believe it unless I read it here.
Can any one help?
From Sheldon Brown's website:
This is the unique size used on some older GT bikes. In a classic Dumb Move, GT introduced a completely un-necessary new "in between" tire size. The current owners of GT have chosen to ignore the needs of those who bought GT bikes, and these tires are no longer available.
If you are unfortunate enough to be stuck with one of these bikes, you do have a serious problem. We carried tires in this size as long as we coud get them, but the supply has been exhausted.
This size is halfway between two fairly uncommon sizes, and you might be able to make do with a slightly wrong size tire.
The next size up, 26 x 1 3/8 (590 mm) is 3 mm larger in diameter. A 590 tire will fit over the 587 rim, but is likely to fit too loosely to work at full pessure, if it even works at all.
The next size down, 650 B (584 mm) is 3 mm smaller in diameter. It is likely to be a struggle to mount one of these on a 587 rim, but if you can get it on it will work, after a fashion. A mismatched tire may not seat properly, so there might be a bumpy ride with one section of the tire sinking farther into the rim than the rest.
Most of the bikes made for this orphaned size used cantilever brakes, so the possibility of making the bikes useful by replacing the wheels is even limited. The two sizes listed above will usually work with the original brakes, but these are both semi-obscure sizes, and rims are harder to find than tires. We do have some rims that could work.
The 584 mm/650B size seems to be undergoing a bit of a revival, so if you decide to replace the rims or wheels, this would likely be the best option.
Actually the ideal solution IS to get a new 650B wheelset made, and 650B tires. 3mm in bead seat diameter difference is only 1.5mm in difference for the position of the brake tracks on the rim sidewall, well within the adjustment range of most cantilever brakes.
I don't post to generate business for myself or make like I'm better than sliced bread
I found a solution. I stopped by the local bike dealer in town here and he told me to put on 26 1 3/8 tires so I went to Walmart and bought tubes and tires. So when my friend went to put them on they were too big. So I called the bike dealership where I first bought the bike and they told me exactly what has been posted here. Impossible to find and these other sizes don't quite work. I decided to go back to the bike shop and have the bike mechanic give it a shot. I figured he seemed to know something. He was a gentleman who clearly knew his business. And guess what ...he did it. He put on the above size tires and tubes and they are not knobby tires and got them to fit on my rims. I took the bike for some short rides and I am feeling comfortable. I was so happy that he was able to get the problem fixed after all that I have read. I know eventually I will need to replace my bike but for now it is working. Perhaps it was a fluke and the tires and tubes were off a little but the point is they work on my bike. I appreciate having my Continum back up and running again. I just love my bike.
Last edited by Ashana; 04-29-2009 at 05:02 PM.
I have a dozen in my basement but won't sell any more of them....Ive sold off a number over the past year. I have both a Tachyon and a Quatrefoil tandem that take 700D's.....but if you PM me I will tell you the name of a dealer that has a good stash remaining. He won't sell more than four at a time. When I was there last he had both 1.4 raised ridge knobbies and 2.0 knobbies. I'd bet there are still over 500 of these tires in the dark basements of shops across the US. I run into them all the time....all one has to do is ask at an old time GT dealer that sold GT's back in 90-91. Dee8 I agree with you on the 650B's also but still feel the best answer on bikes of the 91 vintage is to keep them original if at all possible. Some of the tires I have even have a Schwinn logo on them from the GT/Schwinn era before Pacific.
Needed: 26.8mm XTR seatpost, blue GT/Grundig Jersey.