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matt slegg

Freewheel strength

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Something Ive pondered for a long time, are hube freewheels considered stronger than front screw on or splined freewheels?

Do number of engagement points equal more strength?

Who makes the strongest front screw on or splined freewheel?

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I won't say so.

A screw on or splined freewheel has a bigger diameter (the inner diameter ist bigger than 35mm). Thus the part designer has more freedom in his design. The surface in contact could be higher too. On the other side, having a bigger steel part means much more weight (and having more surface in contact can lead to more drag - but this is negligible).

Another advantage to have a bigger diameter is that the relative backlash (play) is smaller. Using the same machining precision, the bigger the pawls, the smaller the undesired tilt of the pawl will be.(better engagement, may skip less)

A second problem with a freehub is the hub axle itself. You will have a huge load on it and on the freehub bearings and here again the small amount of space available makes things harder to design.

So it seems that having a front screw on or splined freewheel is better. But steel is not cheap (and you have to use steel or titanium due to the forces) and machining a large steel surface even less.

So the build quality of a front freewheel is often not that good compared to the one of a freehub (which is per definition an expensive part).

 

I think too, when embedding the freewheel mecanism in the hubshell, one can use its own strength.

 

To me, the current design of hubs (including those with 12mm axle) could be improved for trial riding.

This is not possible for other mountain bike discplines because one wants a wide gear range and a small chainring. This implies that a small sprocket is required (10t or 11t with current chain standard. Having less teeth will lead to the "polygon effect").

 

I think having both implementations available on the market means that none has a big drawback.

 

Edited by La Bourde

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14 hours ago, matt slegg said:

Something Ive pondered for a long time, are hube freewheels considered stronger than front screw on or splined freewheels?

Do number of engagement points equal more strength?

Who makes the strongest front screw on or splined freewheel?

Just to clarify a few things - when you're saying "hub freewheels", are you referring to a freehub like a Hope, or using a freewheel on a fixed rear hub? If you mean a freehub, they will generally be a little stronger. The biggest weak point of a freewheel is the outer shell, something which isn't the case with a freehub. The constraints on design for a freewheel mean that they can only make that outer shell a certain size and thickness, whereas for the ratchet built into a hub there isn't the same issue.

If you're talking about a freewheel on a fixed hub, the freewheels themselves are the same as those used up front so there's no real difference in that sense. The splined vs. screw-on thing doesn't make much difference. All that will really change is a company will spec either a splined or a screw-on fitment for it. The rest of freewheel core doesn't fundamentally change. Your choice of splined or screw-on will be dictated more by the cranks you get - if you have screw-on cranks, you'll need a screw-on freewheel. If you've got Echo splined cranks, you'll need an Echo splined freewheel. If you've got something like the Clean or Crewkerz splined cranks, you'll need one of their HG-spline type splined freewheels. If you've got the Trialtech Sport Lite Splined cranks, you'll need the Trialtech Splined freewheel.

For engagement points, theoretically the more you have the weaker the design will tend to be as you'll have to have a progressively finer toothed ratchet, but as far as most freewheels on the market got they're all quite close to each other so there isn't a huge change there. There are some shit freehubs out there with higher engagement points where the compromises the companies have made to get that increased number of engagement points have reduced reliability, but there are still strong, high engagement point hubs out there.

In terms of strength of freewheels, the 135-click freewheels you see on the market now (e.g. Jitsie, Comas) are all the same. The 108-click freewheels are all going to be basically the same model too. Things are a lot better as far as freewheels go now than they used to be 5-10 years ago, so choosing one is safer in that sense. They used to be much more hit and miss, whereas now, to be fair, they tend to be much more reliable. You'll still get stories of people breaking any of the ones that are out there, but that's inevitable with any part. If it was me and I had the budget, I'd go for one of the sealed bearing 135-click freewheels as they seem to be holding up well for people, and you get a bit more outer shell stability which should help long term.

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Thank You. Sorry should have been more clear. When I say hub freewheels I mean like Hope or Chris king.

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7 hours ago, Mark W said:

In terms of strength of freewheels, the 135-click freewheels you see on the market now (e.g. Jitsie, Comas) are all the same. The 108-click freewheels are all going to be basically the same model too. Things are a lot better as far as freewheels go now than they used to be 5-10 years ago, so choosing one is safer in that sense. They used to be much more hit and miss, whereas now, to be fair, they tend to be much more reliable. You'll still get stories of people breaking any of the ones that are out there, but that's inevitable with any part. If it was me and I had the budget, I'd go for one of the sealed bearing 135-click freewheels as they seem to be holding up well for people, and you get a bit more outer shell stability which should help long term.

One thing I did not appreciate with the 135-click freewheel I bought, was that there was a HUGE drag! Does it get better after "breaking in"? I sent it back.

7 hours ago, Mark W said:

The constraints on design for a freewheel mean that they can only make that outer shell a certain size and thickness, whereas for the ratchet built into a hub there isn't the same issue.

What kind of constraints? To me it the opposite. You can't increase the size of the outer shell of the freehub to a certain limit (wheel geomerty) and the size of the axle is fix.

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Who else remembers the fun of the ACS claw, 16? 18? 24? point engagements I can’t remember. They would break all the time, what a nightmare to remove them... good times !

 

Todays freewheels are insane, different world. 

Edited by AndyT
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18 hours ago, AndyT said:

Who else remembers the fun of the ACS claw, 16? 18? 24? point engagements I can’t remember. They would break all the time, what a nightmare to remove them... good times !

 

Todays freewheels are insane, different world. 

I hated those freewheels.

When I first got into trials I couldn't afford a chris king hub and front freewheel wasn't really accessible.  I used to buy shimano deore hubs for like $12 each online, and break one every month or so.  The axles tended to break.  Learned to build wheels fast.  The old freehubs has problems with the axles, but newer ones are pretty beefed up.

 

That being said.  I think a quality freehub like a Hope or I9 and also decent freewheels are going to be pretty dependable, so breaking one for most people is either going to be hypothetical or one of the those weird rare things.  Freewheels are a bit more cost effective.  I'm 230 lbs and ride like a sack of bricks and can't remember the last time I broke a freewheel or freehub.

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