27 to 700?
 

hey y'all, i have been riding a self made singlespeed steelframe touring bike for a few years now and have finally decided to go ahead and get myself a flip flop wheel. i am pretty impatient with wheelbuilding. i have 27 inch wheels, and found a 700 flipflop on the internet for 89 bucks. would switching to 700 be a big deal? would they work on a frame built for 27s?? - thanks -drew

well it will be hard to find a frame that can accommodate a 26x increase in wheels size

they work, you'll just have some more space between the tire and your frame. throw on some fenders for when it rains or run super fat tires. or just do nothing. 700s work fine, that's what i'm sure most people did on their first conversions (me included)

you may need some long reach brakes.

:D

Just get a long reach front brake caliper and you'll be fine. The one you have now for the 27" might be long enough too, try it and see.

Older frames were designed for larger diamater wheels and bigger tires than are typical for road bikes today. Switching to 700c wheels will lower your bottom bracket (4 mm if you use the same tire width), slighly altering the handling characteristics of the bike and increasing you're chances of pedal strike when cornering. Pedal strike is less of a problem with a freewheel, but it is a serious concern if you go fixed becaue you can't coast around corners. Using narrow tires (23 or 25 mm) will lower your bottom bracket even more. If you go with 700c wheels, I would use a larger tire to keep the bottom bracket at its intended height. Use at least a 28mm tire with a freewheel and at least a 32mm tire with a fixed gear.

Fat tyres will also help with any brake reach problems

fat tires will not help with brake-reach problems. but then again, you may not even have brake-reach problems. Older brakes tended to be longer-reach.

I personally dont think you'll need to go with bigger tires (4 mil BB drop is a nit), but i say do it and take advantage of all that new-found space. some nice plush 32 or 38 paselas cant be beat imo.

No, they won't. The width of the tires doesn't bring the rim any closer to the fork crown.

And the 4mm BB drop is really pretty damn negligible. So is the drop going to narrower tires (another 2mm? Maybe?). As long as you aren't trying to carve a super-wide slalom course with 175mm cranks you should be fine.

You need about 8 or 10 extra milimeters on your brake calipers.

the wheelset you are buying sounds really cheap which means it probably has suzue jr. or basic hubs. these are total monkey poo, but if you are still testing the waters on this fixed thing they may be good enough for you. just 1) make sure whoever puts on your cog puts it on tight 2) DO NOT under any circumstances try to skid! you will rip the paper thin cog threads right off that hub! i have done it, it's not hard.
if you are more serious, but still thrifty, you can score a formula wheelset easily off of ebay which will be a much much greater value than a suzue jr. one.

more like 4-5. if at all.

I agree that dropping your BB a few mms is not a big deal for normal riding, but it may become significant for an emergency maneuver. 4mm doesn't sound significant, but if you go with a 700x23mm, which is pretty common, that will put your BB about 1 cm lower than 27 x 1 1/8. To me that seems significant, but I would love for someone, given a certain crank length, q factor and pedal width, to calculate how many fewer degrees one could lean before pedal striking. I'd do it, but don't have the time to refresh my geometry skilz.

True. Stupid radius always being half of the diameter.

There has been some misinformation here, and some people correcting it, but let me see if I can sum it up:

-You may have brake reach problems, you may not. You need 4mm more reach, but on a touring frame that might have already had lots of room you may be near the limit.
-Don't worry about BB drop if it's a single speed, and don't worry much if it's for fixed. Also, the smaller tires will make a difference, but not at a 1:1 rate since big tired compress down more than skinny ones. I would not run 35's or 38's unless comfort is more important that speed, I think big tires start to suck at about mile 5 but all I ride is skinny stuff so maybe I'm spoiled.
-$89 wheels will suck, unless it's just the rear, then that's pretty standard for a cheap, reliable wheel. 27 front 700 rear is fine, but if you want to eventually go 700 for both I would do it all at once as the pair will be cheaper than a la carte.

No, No, No, you are adding to the misinformation. You seem to lack experience with big tires. They squishyness is not in proportion to their size, and they will not slow you down very much, if at all. However, they are more comfortable and will allow you to ride in a greater variety of conditions.

OK, let me add "big tires run at the conventional pressure (80ish PSI) compress more than skinny rigs at 120ish, so you're not necessarily going to be sitting 10mm lower on a 25 than a 35." A larger volume tire always has a larger contact patch even at the same pressure, and the contact patch also gets much larger under increased loading, so actually pressure doesn't really matter. Also, I only run skinny stuff now after years and years of running 26 x whatever, 27 x 1.25, and 650B x 35, I know what I'm talking about here. A bigger tire at a lower pressure is more rolling resistance any way you slice it, not to mention inertia. I ride long distances in urban conditions, some might want fatter tires for comfort but I'll take speed, agility, and acceleration any day. I achieve comfort by paying attention to what I run over, and other than snow pack where I wish I had MTB fatties I'm happy with them under all conditions (and in Chicago, we get all conditions).

You can roll over to the rivendell page if you want to read the real arguments in favor of fat tires, but the first premise of everything over there is "speed doesn't matter."

My fixed conversion started with 27's. Had my LBS order my a rear 700 wheel thru QBP. It is a surly flip flop laced to a Mavic Open Pro. Bought a 35 dollar front wheel they had hanging for ages (RSX hub to arraya rim). Both wheels are wearing Specialized all conditions 700x25. I was lucky, the original brakes had enough reach.

Before the bike standover was just a bit tall for me. Changing to 700's made it to where the boys didn't sit on the top tube. I have yet to experience pedal strike. When I have the power grips on the bike, the section of strap that hangs down tends to scrape in tight turns. Oh and I'm running 172.5 Sugino cranks.

Oh yeah. duh

yeah, you are right. Big tires generate more rolling resistance, but given the small ranges of tire size here (23mm-32mm) the average rider is not going to notice a significant speed differernce if everything is properly inflated. MTB tires mostly slow you down because of the high relief tread. If we are comparing slicks the difference is minimal.

Van Dessel
 

First of all - thanks for the amazing response to my question! ill make the switch for sure. I ride with Schwalbe marathon tires which are pretty huge, maybe 32mm, and the wheels im looking at are from VAN DESSEL - which ive never heard of, but they offer a set of wheels at 169 or the flipflop for 89. i am serious about this, but honestly, ive been riding every day with the same steel araya wheels that came with my bike at the thrift store for about 6 years, so i probably wont notice much difference anyway! any ideas about VAN DESSEL's reputation? they look good to me... -drew

please don't do what others have done and put a 700 in the rear and a 27 in front it can make the bike handle really weird get a wheel set and roll it I have a bike that is like that and it works quite well

There are Formula hub + {Weinmann DP-18, Alex, Mavic CXP22} wheelsets all over ebay for $150. The DP-18s are deep section and can be had in any color, which is nice.

Come on. 4mm really going to make that much of a difference? Uneven tire pressure would cause lots of handling problems if this is the case.

try it and tell me how your chopper feels mmk
it will effect handling in the way a raked fork would another one that is a bad idea is 650front and a 700 rear on a normal frame


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