Phatman

I'm wondering why a company has not made a fixed gear hub that uses a shimano spline pattern that is just stationary and fixed to the hub? it seems to me that if you did that you could use regular old shimano cassette cogs which are cheaper then the track cogs (9 for $20 in assorted sizes!), and would be easier to take off (no chain whip needed). It seems to me like that would be the way to go. you wold never have to worry about locktighting your lockrings or anything.

Has this already been done before? is there something I am missing?

tommasini

Surly makes the Fixxer, which replaces the freehub body and allows you to run a track cog, but it is kind of expensive, about $70 at most places
https://www.surlybikes.com/hotmetal/parts_Fixxer.html
I just finished my second fixie, welded a freehub body together and am running one cog from the cassette...this works OK so far, but am trying to find a Shimano BMX cog (about $5) as the tooth profile works better for FG/SS and the spline pattern is the same. Got the idea for this at
https://www.m-gineering.nl/trackg.htm
However I didn't bother dissasembling the freehub body as described on the page, just tack welded at three spots on the back and then ground the welds flat using a grinding stone in a drill press so that the freehub would seat properly (level and perpendicular) on the hub.
Miche makes an adapter for fixed hubs that uses splined cogs, but AFAIK the cogs are a unique spline pattern and are not cheap

roadfix

[QUOTE=Phatman]
Has this already been done before? QUOTE]

Miche splined cogs

Gonzo Bob

I would think you could have a lot of problems with the chain coming off since the cassette cogs have smaller, profiled teeth to allow the chain to disengage/engage eaiser.

Before I bought track cogs for my fixie, I tested what gear I would need by putting in a multi-speed wheel from another bike. The chainline looked good on the cassette cog I chose but it still jumped off to a smaller cog twice during the 1.5 hour test ride.

shecky

The BMX splined cogs have full sized teeth as they were intended for single speed BMX bikes. Most seem to cost in the $5-$10 range.

It would be a good idea. The splines could also be done to accept both Shimano and old Bendix/Sturmey Archer/Sachs cogs, too, which can often be found even cheaper.

Phatman

one thing I didn't think about, is the shimano spline pattern patented?

Dorf411

So you haven't had any problems with this setup? I had a hub body welded as you describe and it was done very well but I had a very bad outcome. I got 8 of my 12 mile commute and just starting to get the hang of it when my wheel siezed up. For some reason the 10mm fixing bolt that holds the hub body to the hub unscrewed itself causing everything to bind up internally. I decided it was a bad design and scrapped it. Perhaps it had something to do with using a quick release vice solid axle. I was lucky I was fairly near the trolley station when this happened so I could ride the trolley the last 4 miles. Then there was the walk of shame the remainder of the way to the office.

tommasini

yikes!...that doesn't sound good. The bike in question has only been for a very short test ride as I built it for my brother as a gift and it is too small for me (and I have my own fixie). I wonder if anyone has has a similar problem with the Surly Fixxer? I did switch to a solid axle, don't know it that will matter. Actually, I already advised the new owner to buy a flip-flop hub and build a proper FG wheel if he gets hooked on fixed riding as I expect...hopefully it will work OK long enough to check it out at least. Anyway, thanks much for the warning, I will pass it on with the bike...

shecky

I dunno. There are compatible third party cogs out there from Chris King, Novatec, and sevral more, as can be seen here: https://www.danscomp.com/cgi-bin/haze...ELS/index.html

superchivo

The unscrewing problem would make sense since the Shimano free hub mechanism is designed to be self tightening when you pedal forward (see the freehub chapter of the manual in the mechanics forum). Since that which can be screwed can be unscrewed...ouch.

xcutterx

i don't think shimanos are seld tightening. don't the splines keep it in a fixed position? i know mavic and spinergy style freehubs that thread on would come undone but wouldn't a shimano stay in one position since the bolt holds it onto the splines? i welded a friends shimano freehub and he got a DX cog and has had no problems so far. he doesn't ride it a lot but it seems to be working thus far.

smurfy

A friend of mine gave me a NOS Shimano high-flange rear hub that has a freehub body that accepts 3-speed/coaster-brake style cogs and a hog ring. He used to race BMX back in the late '80s so I guess it's meant for that. I've never heard of these before but maybe something like this could be used for fixed-gear applications. A 1/8th chain would have to be used, however. I'm using this hub for an English 3-speed I'm converting into a SS.

superchivo

Cutter,

The splined freehub assembly (bearings, pawls, and all) is removable from the hub body with a 10mm allen wrench. It is designed to self-tighten with the tension of forward pedaling. If the pawls were jammed up to create a fixed gear situation, I would imagine you could back the assembly out of the hub by pedaling backwards.

On further reflection, the assembly might not be able to back out if the wheel is tightened down in the dropouts. Only guessing here, but you might have issues with deforming the bearings / cones or stripping out the threads that attach the assembly to the hub body. I guess you could lactate it. I mean how often do you remove the freehub assembly from a wheel?

Schiek

I don't know what kind of weird s**t you are into, but I have never seen a lactating bike.

tommasini

thats not quite right...the 10mm bolt only holds the parts together, rotation of the freehub body is prevented by the splines as the other poster mentioned, just like w/ the newer splined bottom brackets. The problems w/ the other welded hub may have been caused by other factors (maybe the freehub body wasn't seated properly?)...the Surly Fixxer works the same way and I have read of welded freehub bodies that are trouble free. Personally I would generally agree that hacked fixie wheels are best for checking out fixed gear and should be replaced by a real FG wheel if the bike gets much use (though I'm still running a welded BMX freewheel)

superchivo

Though it pains me, I will admit that a misreading of the Barnett manual and a lack of attention on my part while disassembling a hub have caused me to provide inaccurate advice.

Tom is correct about the splining issue. When I removed the freehub from the wheel, I failed to make the connection between the splines on the back of the freehub body and the mysteriously matching splines on the inside of the hub.

Call me a lactating dork, I guess.

Mine'sAPint

A fixed cassette hub:

https://www.webcyclery.com/.docs/prod...t_details.html

Unsure what it's really intended for, but it's kinda interesting!

legalize_it

its intended for trials riders. bc trials riders use such small gear ratios, some people prefer to use cranks that you thread a standard freewheel onto. if you are riding a "modified" trials bike (20" wheels), you use the freewheel up front, and a fixed gear on the back. mod bikes are always SS. but if you ride a stock trials bike (26" wheels) you generally use multiple gears w/ a derailleur. the fixed cassette hub is used for a stock bike w/ multiple speeds which uses a SS freewheel up front. to compete on a stock trials bike you must have at least 5 working gears.

Phatman

thats exactly what I was invisioning! that is incredibly cool. why don't more people in the fixie world use this? its ingenious!

If only I knew how to build a wheel, I'd be on my way to converting htat bianchi of mine...

roadfix

If I was gonna spend money on a fixed cassette hub, it makes more sense to just buy a track hub instead.