# Horrizontal dropouts and wheels coming off. on fixies



## limzjun2002 (Oct 22, 2005)

Hey to all...new to the forum 

Me lbs said that there is a potential for the wheel to come off horrizontal front-facing dropouts as opposed to regular back-facing track dropouts. This obviously leads to 'interesting' results. He reasons that as one pedals forward there is forward pull to the wheel and cog, hence the risk of the wheel coming off.

Is this possible? Perhaps resident experts can share their 2 cents

thanks 

cheers


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## Dave Hickey (Jan 27, 2002)

As long as you use track nuts and not a quick release, it is no problem. Track nuts hold the wheel very tight... Is it possible, yes. If the wheel is tight, very unlikely. Also, even with rear facing track ends, if the wheel comes loose, the chain can get stuck causing equally "interesting" results...

I don't want to guess on the LBS's intentions, but perhaps they want to sell you a track frame vs you using an older horizontal dropout frame....


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## TurboTurtle (Feb 4, 2004)

limzjun2002 said:


> Hey to all...new to the forum
> 
> Me lbs said that there is a potential for the wheel to come off horrizontal front-facing dropouts as opposed to regular back-facing track dropouts. This obviously leads to 'interesting' results. He reasons that as one pedals forward there is forward pull to the wheel and cog, hence the risk of the wheel coming off.
> 
> ...


There is no more forward pull on a fixed than there is geared. Forward facing, horizontal drop outs were run for a lot of years. - TF


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## climbandcycle (Nov 4, 2004)

*Figure I'll chime in before this goes way off topic*

TT is a little misguided. The linear force when pedaling forward is the same but when you shift your pedaling to slow yourself you create tremendous (more than you ever will sprinting) amounts of torque. This torque transfers to the bottom of the chain as a forward pull, if your wheel is not secure in the dropout it can pull the wheel out of its dropout. I have had many converted road frames and a track frame and never had a real issue with this because I use track nuts on my wheelsets. 
I tried a hex quick release and after multiple stops I had moved the hub about a 1/4", after trying to make it tighter with the same results until i snapped the shaft, I scrapped that idea. Many people will try to tell you that QR with fixed wheelsets work, try it for yourself and you may find that your riding style is too aggressive to use one, but I would be weary, especially with forward facing dropouts. 

So in short, your lbs is correct in one regard, but if you properly torque your bolts you have nothing to worry about...


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## TurboTurtle (Feb 4, 2004)

climbandcycle said:


> TT is a little misguided. The linear force when pedaling forward is the same but when you shift your pedaling to slow yourself you create tremendous (more than you ever will sprinting) amounts of torque. This torque transfers to the bottom of the chain as a forward pull, if your wheel is not secure in the dropout it can pull the wheel out of its dropout. I have had many converted road frames and a track frame and never had a real issue with this because I use track nuts on my wheelsets.
> I tried a hex quick release and after multiple stops I had moved the hub about a 1/4", after trying to make it tighter with the same results until i snapped the shaft, I scrapped that idea. Many people will try to tell you that QR with fixed wheelsets work, try it for yourself and you may find that your riding style is too aggressive to use one, but I would be weary, especially with forward facing dropouts.
> 
> So in short, your lbs is correct in one regard, but if you properly torque your bolts you have nothing to worry about...


I lot misguided. Listen to climbandcycle, not me on this one. - TF


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## djg (Nov 27, 2001)

*dunno*

that I can tout any particular "expert" credentials, but I'll side with the others: if you've got proper track nuts and torque them down right things just shouldn't move much at all, in which case the direction of the slot in your dropouts (or fork tracks) is less of a big deal. Plenty of folks use old style, front-facing, horizontal road dropouts. Properly secured, they should be fine. With a crummy quick release running through a hollow road axle (and there are some crummy qr levers out there), all bets are off.


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## Jamieshankland (Jan 8, 2005)

Its a load of crap. The tention you put on the chain pedaling is the same as if you have a cogset and not just a fixed cog. The same goes for the argument about sold axle / QR hubs. A qr holds the hub in just fine in normal circumstances why not while its fixed gear? I run my winter crosser fixie with QRs.


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## TWD (Feb 9, 2004)

Jamieshankland said:


> Its a load of crap. The tention you put on the chain pedaling is the same as if you have a cogset and not just a fixed cog. The same goes for the argument about sold axle / QR hubs. A qr holds the hub in just fine in normal circumstances why not while its fixed gear? I run my winter crosser fixie with QRs.


I can't speak for anyone but myself, but I put a lot more force into the pedals riding fixed and SS than I do on a geared bike. There's no way around it, I've gotta get up the steep hills somehow. Of course, lower cadence will mean greater force per revolution given the same overall power output (assuming I climb a hill at roughly the same speed fixed vs. geared but with higher cadence geared).

I'm using an older road frame with forward facing horizontal dropouts. When I first converted it over to SS, I was running it with a QR hub (using a shimano skewer). I had all sorts of problems with the hub shifting in the dropouts, causing slack in the chain to the point I was throwing the chain regularly. Not the end of the world on an SS, but would rather that didn't happen when running fixed.

Never had any noticable slippage with the same hub and skewer running it geared.
Haven't had any issues funning SS or fixed with flip/flop with track nuts on it (not including the 1 time I didn't properly torque the nuts).

The only other explanation I have, is that the dropouts on my frame have a worn spot from years of use as a geared bike, and the required shift in axle position to get the proper chain tension put it just outside of that position. I think a minor bit of slippage may have caused the wheel to shift forward into that old position, causing quite a bit more slippage and the chain tension issue.

Something to consider on a Fixed conversion I suppose. Still, running a hub with track nuts is the safest bet.


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## climbandcycle (Nov 4, 2004)

Jamieshankland said:


> Its a load of crap. The tention you put on the chain pedaling is the same as if you have a cogset and not just a fixed cog. The same goes for the argument about sold axle / QR hubs. A qr holds the hub in just fine in normal circumstances why not while its fixed gear? I run my winter crosser fixie with QRs.


You are correct in that the forces are the same while "pedaling". However, the force generated, under constant forward velocity, when you brake with your legs is more force than you could generate while pedaling when moving forward. Match this with the oscillation of sprint to full braking and you may work the axle forward. If it does move forward the extra slack in the chain will only increase the difference in force when pedaling forward and immediately resisting. The small time where their is little resistance allows for you to become rigid and allow for maximum recruitment of muscle fibers for braking. These different forces summarize why the forces on a fixed drivetrain are much greater than a freewheeled drivetrain, and why you may pull the axle from a forward facing dropout.


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## Jamieshankland (Jan 8, 2005)

I've lost count of how many Fixies i've worked on and how many guys I ride with a QR and forward facing drop outs. I've yet to see a hub slip out. Most these guys arent little wirey guys either. All of us are sprinters of some sort. My last years training bike had a 48/15 gear. I sprinted and muscled up hills. Not once did my wheel slip. As for the comment about back pressure being stronger, You could'nt be more wrong. Any coach/trainer will back me up there. The required force to shift your axle would spin the cog off first or lock your wheel. Espessialy if your smart enough to run propper tention in the QR lever. 

Reasons why wheels shift:
-your girly arms didnt tighten the wheel down enough
-your chain line is off alot
-your dropouts are chewed up and or not square
-the axle locnuts have no bite left in them.

I'm not trying to sound like a dick, just arguring against some misconceptions about fixgear stuff.

I say good day.


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## danl1 (Jul 23, 2005)

One unseen factor in the equation is that of gearing. The differential described exists on a fixie, though it's somewhat limited because once the wheel begins to skid, the force drops off dramatically. 

Also, the fixie has gearing of say, 70-75 gear inches. But as a geared bike, those same dropouts could have had gearing in the 28-34 inch range, and possibly against longer cranks as well. So for a fair comparison of the forces a horizontal drop is capable of handling, we should compare hammering and stalling out a granny gear against the force of resisting a fixie. There, the difference is slimmer, and I'd believe it if someone told me it went the other way. 

I believe that the forces are greater on a fixed drive train. I don't know how much greater, and don't have a way to quantify it. But I suspect that they are within reasonable tolerances. 

Here's another way of looking at it. The reasonable worst-case scenario is not the wheel coming free. Before that would happen, the wheel would twist sideways and lock up against the chainstays. Ground friction keeps the wheel rearward, and the chain torque translates into twisting the wheel in the dropouts. That same problem exists equally for horizontal (front entry) dropouts and horizontal (rear entry) track ends, unless your gearing just happens to bottom out the axles in the track ends, or you ride with chain tensioners. 

Except for one factor - the horizontal dropouts are more secure than the track ends. Why? Because the downward angle of a dropout provides some measure of resistance. Picture pulling the chain against nearly vertical dropouts vs. nearly horizontal ones, and you'll picture the force I'm discussing. If it's not a problem for track ends, it's less a problem for horizontal dropouts.

Still, give your nuts a good twist before you ride.


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## limzjun2002 (Oct 22, 2005)

Thanks to those who replied. Really appreciate your effort 

_____________________________________________________________________________

Thanks

Cheers


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