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Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 12:19pm
by LittleGreyCat
Looking at bikes (and drooling) I noted that some come with the option of 26" (650C) or 700c (27") wheels.
Whilst noting that the smallest frames seem to come with 26" wheels and the largest frames with 700c which doesn't seem unreasonable there is quite a wide overlap in the middle range.
I read that the real measure of speed/performance is the "gear inches" and that you put different ratios on the 26" and 700c transmissions to roughly maintain the same "gear inches".
So a pondering moment. Assuming that the derailleur has a maximum and a minimum range that it will handle, does it mean that a 26" wheel setup has the potential to be geared lower (at the extreme) than a 700c setup? Conversely does a 700c setup have a potentially higher maximum gear? This is assuming that the front ratios have the same maximum and minimum gearing (because frame not wheels).
I do note that the actual wheel circumference is also dependent on the tyre profile.
Alternatively, would you go for 26" and fat tyres or 700c and skinny tyres? Ultimate top speed versus comfort and versatility? Same circumference and gearing, different ride.
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 12:59pm
by meic
Your post doesnt really have a question in it and I would agree with most of your thinking.
However if i was you I would take a closer look at some of the (crazy) terminology for the wheel sizings.
More commonly 26" would refer to 559 etro traditional MTB size
27.5" 650b would refer to 584 etro
27" would be 630 etro (an out of date size)
28" is 700c would be 622 etro (the 28" name isnt common in the UK but you will see it on the side of the tyres, for the German users)
29" is the same 700c rim fitted with a much bigger tyre still 622 etro.
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 1:12pm
by TrevA
The formula for calculating gear inches is - Chainring size (no of teeth) X Wheel size in inches/Sprocket size (no of teeth).
So if 700c is nominally 27 inches (it isn't, but can be used for this purpose) and 26 is 26 inches, the equivalent gear on a 700c wheel will be larger.
52 x 27/15 = 93.6.
52x26/15 = 90.1
Obviously, tyres make a difference too.
26 inch wheel will be stronger for a similar spoking.
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 3:08pm
by Brucey
LittleGreyCat wrote:Looking at bikes (and drooling) I noted that some come with the option of 26" (650C) or 700c (27") wheels....
it is "700C" not "700c". There are 700A, 700B, 700C, 700D, 650A, 650B, 650C rims and tyres and each of the rims is different. Each of the rims was originally designed for one size tyre only but in popular sizes there are different width tyres available that fit the same rim. The "700C" nomenclature is a now obsolete French system. They pinched the rim and tyre sizes themselves from a British system that is at least 110 years old. So for example 650B is actually 26 x 1-1/2" and the defining feature of both is that the rim has a bead seat diameter of 584mm and the standard size tyre is about 1-1/2" wide (unless stated otherwise). The 650C rim is an oddball one; it was actually meant for 1-3/4" section tyres but in recent years 650C rims (571mm) have mostly been used with skinny tyres, giving a wheel that is about 25" overall diameter.
https://web.archive.org/web/20160221203327/http://www.harwoodcycles.com:80/tyre_size.htmhttps://sheldonbrown.com/tire-sizing.html Alternatively, would you go for 26" and fat tyres or 700c and skinny tyres? Ultimate top speed versus comfort and versatility? Same circumference and gearing, different ride.
It takes a very fat 559 tyre to run at the same overall diameter as a very skinny 622 diameter....
If you want to take the tyre size into account when working out gearing without frying your grey matter it is easiest if you use a gear calculator like this;
http://ritzelrechner.de/?GR=DERS&KB=34,48&RZ=11,12,13,14,15,17,19,21,23,25,28&UF=2100&TF=90&SL=2.6&UN=MPH&DV=gearInches&GR2=DERS&KB2=34,48&RZ2=11,12,13,14,15,17,19,21,23,25,28&UF2=2135where you get to choose the tyre size from a drop-down menu. As above, it is set to compare gearing for 54-559 tyres with 25-622 ones.
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 4:08pm
by PH
You ought to be able to get the gears you want whichever wheel size you choose, IMO it's the wrong criteria for choosing.
The theory is - small wheels accelerate faster and are stronger, larger wheels roll better over bumps and hold their speed. I say theory, I think it's more than that, each of this things are provable, the theory comes when deciding which are important to you and how much difference you're likely to notice. I dislike 26" wheel bikes, every one I've owned has felt like hard work, but I've never owned two otherwise identical bikes, so what I'm attributing to the wheel size may be something else. I also dislike the aesthetics of bikes in my (Large) size with 26" wheels, I don't know why, I don't dislike the look of my folder, but there it is...
There's a few other practical considerations, 26" are apparently more readily available in some remote parts of the world, there's more road tyres available in 700C and more chunky tyres in 26" (Though the gravel trend has changed that somewhat) 26" has stopped being the norm for MTBs so future tyre choice may become restricted.
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 4:12pm
by Greystoke
Personally on a touring bike I'd go for 26", stronger and lowers the gearing and step over height. Trouble is finding a good mid price bike with 26" wheels, most bikes are now 700c so you don't really have a choice anymore.
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 5:11pm
by rmurphy195
I would "separate the 2 concerns", personally.
Choose the rim size depending on what you want, aesthetically, or type of readily available tyre,or where you are (some hints in the other posts).
Then sort out the gears as a separate task, miing the chainring and sprocket sizes to get the gearing that you want using a chart that is available on the CUK website somewhere, or just google it.
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 5:35pm
by horizon
Assuming your own height doesn't push you to 26" wheels in a small frame, I would go with your intended use. More heavily loaded over rougher ground then 26", lightly loaded over tarmac then 700c. Ironically a larger wheel will roll better over rough ground but this is trumped IMV by strength of the smaller wheel and the wider tyre. I have both sizes and am happy with both.
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 7:34pm
by mercalia
with 26" it is easier to get low gears with standard parts ( dont have to use very large rear sprockets and there fore a rear derailleur to cope ) If you use fatter tyres your can make a 26" wheel into a much larger/taller wheel as fatter tyres are taller?
on my Dawes 1-Down the largest rear sprocket is 30 and the front are 46/36/26 with 1.75" Marathons. seems ok to me
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 10:26pm
by Nigel
PH wrote: There's a few other practical considerations, 26" are apparently more readily available in some remote parts of the world, there's more road tyres available in 700C and more chunky tyres in 26" (Though the gravel trend has changed that somewhat) 26" has stopped being the norm for MTBs so future tyre choice may become restricted.
The original question was around 650B (584etro), not the (old) 26in MTB (559 etro) size. I'd be surprised if there is anywhere in the world where the 650B is the most commonly available tyre.
Personally, I'd pick 700C unless there was a good reason around a small frame size. Properly built wheels are not going to fail. Frames with adequate clearance for fat tyres are available. Gearing can be adjusted by appropriate part selection. And there are far more 700C tyres to choose from, and a far larger installed base meaning they'll still be around in 5 or 10 years time at any bike shop.
- Nigel
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 10:44pm
by PH
Nigel wrote:PH wrote: There's a few other practical considerations, 26" are apparently more readily available in some remote parts of the world, there's more road tyres available in 700C and more chunky tyres in 26" (Though the gravel trend has changed that somewhat) 26" has stopped being the norm for MTBs so future tyre choice may become restricted.
The original question was around 650B (584etro), not the (old) 26in MTB (559 etro) size. I'd be surprised if there is anywhere in the world where the 650B is the most commonly available tyre.
I don't think so Nigel. Sometimes you have to look past what's written to understand what's meant.
Looking at bikes (and drooling) I noted that some come with the option of 26" (650C) or 700c (27") wheels.
Whilst noting that the smallest frames seem to come with 26" wheels and the largest frames with 700c which doesn't seem unreasonable there is quite a wide overlap in the middle range.
The question did refer to 650
C but was about those bikes that come in a choice of wheel sizes. Which sizes do you think they are
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 10:58pm
by Brucey
Nigel wrote: The original question was around 650B (584etro), not the (old) 26in MTB (559 etro) size...
actually he said 650C. Not a size used on many touring bikes these days.
But talk of small frames with 26" wheels and larger ones with 700C wheels sounds like the Surly long haul trucker to me, in which case it is 559 vs 622. You get a choice of wheel sizes in middling and large frame sizes only with this frameset.
My take is if you are riding mostly loaded, and/or on rough surfaces, choose 26" since this gives you stronger wheels and more wide tyre choices that fit easily. Otherwise 700C is a better choice for unladen road work.
IIRC the 26" LHT frames accept wider tyres than the 700C ones; the fork length seems to suggest that this is the case; the rim radius is different by 31.5mm but the forks are only 14mm different in length.
cheers
Re: Tourer - 26" or 700c wheel?
Posted: 25 Oct 2018, 11:41pm
by gregoryoftours
I'd go with 700c unless you plan to ride very rough terrain, in which case consider the more modern and common (than 26") sizes of 29er (same size as 700c but frame likely to have wider tyre clearance) or 650b 27.5". Most of the bikes I tour with are actually old 26" rigid mountain bikes (559) but it's getting increasingly difficult to find good quality 26" wheels, especially for rim brakes, and especially 36 spoke. You can certainly get them easily via tinterweb shops but they are increasingly rare to find if you have wheel trouble while on tour and looking around bike shops. A couple of years ago I had freehub failure in France and eventually after several hours looking around several bike shops in a decent sized town, found one 26" disc Wheel the flat sidewalls of which were suitable for rim brakes but that had been painted for disc use, so my trip was saved, although the brakes squealed like a stuck pig for about a week until the paint had worn through.
Re: Tourer - 26" or 700c wheel?
Posted: 26 Oct 2018, 9:28am
by Brucey
out of interest what was the mode of freehub body failure?
cheers
Re: Tourer - 26" or 700c wheel?
Posted: 26 Oct 2018, 9:32am
by meic
IIRC the 26" LHT frames accept wider tyres than the 700C ones; the fork length seems to suggest that this is the case; the rim radius is different by 31.5mm but the forks are only 14mm different in length.
26 ̋ frames have clearance for 2.1 ̋ tires;
700c has clearance for 45mm tires;
individual tire and rim combos affect tire clearance
https://surlybikes.com/uploads/download ... NST_vF.pdf