28" vs 26"
 

Hi guys.

I'm a not very experienced SS messenger. And I've been thinking about something. There are some fixie and SS messengers around and they all have 28" wheels. Heck, even the mountainbikers are switching their wheels!

But wouldn't 26" wheels be a better option? I mean cause messaging includes so much stopping, starting, accelerating and uphill climbing.

Or is the 28":ers really rolling that fast?


-Maybe I should buy a trackbike...

not really sure what you mean, are you saying that 26" wheels have less inertia than 700's?

Would someone please explain the 26", 28", 700c thing for me?
Don't I hear the dirt guys talking about 29"?

dolface - smaller wheels get better acceleration if that's what you're asking.

ken cox - 26" wheels are what are on mountain bikes, have a 559mm bead seat diameter (bead of the tire), 700c wheels have a 622mm bead seat diameter, as do 29" wheels. 29" is the same as 700c but a wider rim for offroading, more of a marketing term.
I'm guessing that by 28" the original poster is referring to wheels with a 622mm bead seat diameter, a common size. Plus, apparently 622mm has also been called "28 x 1 5/8"

for more info go here http://sheldonbrown.com/tire-sizing.html

Yes, as I've understood it. The rotating weight is the weight that really counts. But only when accellarating.

I think that's easy to comprehend, to some extent anyway.

And you have to accellerate a little even to just keep the speed you know. (if you are not riding in vacuum, and non friction floor and hubs)

fwiw, I'm pretty sure that whatever minute difference there is in inertial moments of 26 v 700 wheels isn't going to drastically affect anyone's performance as a messenger. Training yourself to lock up your bike in under two seconds or climb stairs four at a time would result in a significantly larger improvement in your messengering than fretting over specific bike geometry/component issues.

How can someone put LARGER wheels on a bike?

Secondly, if I follow your logic to its conclusion, wouldn't 12" wheels have even less "inertia"? Shouldn't we all be riding pixie bikes? Or rather a "pixie TALL bike" so we fit? Wouldn't a dahon folding bike be the fastest thing on the road? How about using scooter tires? Casters?

I don't think so.

It is my understanding that larger, thinner wheels has less rolling resistance.

This is one of those weight weenie things that most people dismiss because the actual savings is not that great. You would do better by dropping a few pounds off your body than by doing anything to the bike. Plus the 700C tires are typically narrower resulting in less rolling resistance.

I am sure Boston Trevor has done the calculations at some point...

ok, i was just trying to understand what you were asking.

i'm pretty sure that unless you're racing at a world-class level the inertial difference between the two sizes is unnoticeable, so i'd say stick with what you have, and don't worry about it.

Ha! I haven't but now I'm half tempted to go out and track down rotational inertia formulae and figure out what the exact difference is.

Bigger wheels roll over bigger stuff. This was one of the big advantages of the ordinary over the boneshaker. It took Dunlop's pneumatic tire to bring us back to relatively small, equal-sized wheels without rattling our teeth loose.

Some 26" frames can fit 29" wheels. Case in point: the Surly 1x1. I've done some looking at my MB-2 and I think it might work too, but I'm not particularly interested except in an idle "I wonder" sort of way. It messes with the standover height and handling and you need to change up your brakes (there are canti extenders or you can go disc if you have a discable frame).

I have been doing research on this 29er thing. Test rode a full sus 29er, and the rolling was great. Has me wanting to build up a SS29er. Well anyways, I noticed that some refer to them as 28 inch tires, like the Fat Alberts by Schwalbe. Funny on mtbr's 29er forum, some hate hearing the 28 size reference. It wouldn't get the same backlash as posting in here that you just got the sweetest track frame ever, and added a back brake mount, back brake, and a freewheel.

I like 26" wheels, but I'm also not all that tall.

The difference in acceleration, all other things being equal, is pretty much negligible.

This might help you with your wondering

Surly 1x1 convert http://forums.mtbr.com/showthread.ph...0&highlight=28

IRO Mia convert http://forums.mtbr.com/showthread.php?t=101784

Well I'm just alot into (trying to) optimizing my life. I'm also about to buy a new bike so I have to figure out witch way to go.

For me it's pretty clear 28" wheels is the best for road racing, I mean that's what everybody use.

While messaging is still on the road it's very different I think from racing. I terms of slowing down or stopping all the time just to take up the speed again. And also a smaller wheel would be tougher, witch is a big issue when messaging as everything wears and brakes.

So, the bottom line is: If a 28" wheel is optimal for road racing then a smaller wheel would be optimal for messaging.

Question is if the optimal is closer to 26" or not.


Or... of course I could be missing something. I generally do in my quest to optimize my life. :)

You're thinking too hard.

You could put thinner, lighter tires on your 700c wheels... I just put some 700x32's on a wheel that had been running 700x23's for 6 months in order to handle the local potholes and unpaved paths/river trail, and I noticed the HUGE difference in inertia (in the opposite direction). I may go back to the 23's when the road crew has had time to patch up all the winter potholes, but by then I'll want the 32's to deal with the snow.

The design of the rim is more of an issue than it's nominal diameter. If I RELIED on my bike, I don't think I'd have a problem with a little extra rotational inertia if it built a stronger wheel.

I know... But I can't help it.

This really supports my theory! *very exited* Do your bike feel heavier when climbing uphill or is it just slow when accellarating? Or both?

I've mostly felt it while accelerating, but it's a tradeoff that I'll make to have a more comfortable ride. The difference probably isn't that great, and I may even ride faster since I don't feel as though I have to slow down for poor road conditions, and I may just be a little too "Detail-oriented" or "anal-retentive", depending on your point of view. I still prefer the ride of the thicker, lower pressure, grippier tire to the one that may be faster.

http://www.moultoneers.net/new1.jpg?

fsnl
sparky

Yeah, well... Maybe that one wouldn't be my first choice for messaging despite it's small wheels and great looks. :)

i've ridden one of these bikes, it was quite smooth, comfortable and felt almost like a road bike. but the sight of it was enough not to want one.

there is a alight benefit for 26 wheels as stated above but wouldnt the increased friction produced by hubs rotating at a higher rpm cancel it out?

Off course your reasoning is right to some extent but I don't think the hubs increased speed friction will be noticable, though the bearings will wear out a little bit faster.

No the big wheels advantage is the ground will relatively towards the wheels be more flat if the wheels are bigger. And that is very noticable. We all know a flat road is faster than a rough one.

But I also think the lesser inertia with smaller wheels is noticable. But it's only when starting and a little bit when accelerating and uphill.

Off course you are rolling all the time and only accelerating sometimes...