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 Front fork disc brake mounted gear
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ElectricStreamliner
recumbent enthusiast

Australia
100 Posts

Posted - 02/11/2020 :  23:22:33  Show Profile  Reply with Quote
I saw this in the "fbb fwd mwb dvps" thread and think this deserves another thread rather than hijacking.

quote:
Originally posted by Balor

I think the narrowest possible 'drive' hub is front hub with disk brake replaced with a sprocket.
You can even retain disk brake capability by using a hub like this:
https://ru.aliexpress.com/item/32887090011.htm

(been eyeing it for a while)



How do you do this?



I can imagine that chain two can use the inner most cog while chain 1 utilities the rest or vice versa.

alevand
human power expert

USA
3979 Posts

Posted - 02/12/2020 :  06:56:34  Show Profile  Visit alevand's Homepage  Reply with Quote
one way:

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Tony Levand
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Balor
human power supergeek

Russia
1217 Posts

Posted - 02/12/2020 :  07:14:36  Show Profile  Reply with Quote
What you want looks a lot of like Tetz drivetrain from his streamliner:

http://www.recumbents.com/mars/pages/proj/tetz/VFS/projtetzVFS01features.html

I don't think it would work for someone who's legs are not very skinny.
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SpiderMonkey
recumbent guru

USA
943 Posts

Posted - 02/12/2020 :  07:20:10  Show Profile  Reply with Quote
RE caliper placement: The NoCom caliper is mounted directly on the bottom of the fork. This has always worked just fine in my experience. I'm sure some would argue that it makes it somehow more prone to collecting dust or water, but I have not found that to be the case -- but of course the NoCom doesn't get much gravel time, and very little mud time.



Should be simple enough for you to weld an ISO mounting tab to the bottom of the fork.

--SpiderMonkey
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alevand
human power expert

USA
3979 Posts

Posted - 02/12/2020 :  07:41:41  Show Profile  Visit alevand's Homepage  Reply with Quote


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Tony Levand
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SpiderMonkey
recumbent guru

USA
943 Posts

Posted - 02/12/2020 :  09:26:14  Show Profile  Reply with Quote
That's a regular-width hub on the performer front end. I bought one of those bikes and returned it after a week (2x100 mile test rides). One reason was the hinge assembly. It squeaked non-stop after 20 miles. No amount of tightening, lube, or thin-plastic-sheet shimming could stop it.

The other was more relevant to this discussion. The large idler-wheel assembly was never quite right. The toothed idler pinged back and forth on its axle, which was annoying. More annoying yet was that the bearings seemed to be really undersized. After 200 miles, they were so gravelly that they made a low-grade rumbling the entire time I pedaled.

Any idler with a chain bent like that needs some really stout bearings. It's a solvable problem for you, but I didn't want to solve it on that bike. I lost faith in the build and Q control.

Other issues I had with it that bear consideration for similar projects: It didn't have sufficiently low gears for the terrain in Northern Virginia (and I didn't take it to anywhere especially hilly). The range with stock crank (42-56) on the 451 wheel with an 11-32 cassette was 26-103 gear inches. (My Nocom is 29-130 with an 11-26 on the back.) Kind of the worst of both worlds: lousy low end and lousy high end. (It was a fast bike, so you'd want to push it on long downhills, and I'd spin out.)

Another was that it would have been a pain to get a larger tire on than the 28mm it came with. The fork had no clearance, so I would have had to make a set of 406 wheels, and even then, the fork top was narrow, so I don't think a 40 would have made it.

Finally, I was not a fan of FWD. The twisting chain gave me most of the same clearance/steering problems I had with the NoCom (no tire rub at least) and it also slipped a lot on me -- whenever I had to leg it up a shaded hill where there was rainwater and/or pollen scum, I'd get a decent amount of tire spin and power loss.

And another finally. It had pretty squirrely handling. I'm used to the NoCom, and I felt like this bike took more to stay on top of. The short wheelbase may have been part of that. It was reportedly 93cm, which doesn't seem right. I think I have an email where they told me it was 100. Still reported as 93 on their website: https://www.performercycles.com/recumbent-bikes/folding-recumbent-front-wheel-drive/

I rode a couple of 100 mile rides on it and never felt like it was dangerous, but I did feel like I spent more energy than usual correcting my course.

--SpiderMonkey
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alevand
human power expert

USA
3979 Posts

Posted - 02/12/2020 :  10:23:47  Show Profile  Visit alevand's Homepage  Reply with Quote
I have Performer trike and made many mods to get it right, steering geometry was way off.

The thread is how FWD and disk brake works, not idiosyncrasies of a particular manufacturer.



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Tony Levand
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ElectricStreamliner
recumbent enthusiast

Australia
100 Posts

Posted - 02/13/2020 :  00:28:17  Show Profile  Reply with Quote
Rather than using idlers and one chain. I am talking about attaching two chains to a rear cassette.

The purpose of this exercise would be to use one of those nice 10cm width carbon forks without chopping it up.
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Balor
human power supergeek

Russia
1217 Posts

Posted - 02/13/2020 :  06:26:08  Show Profile  Reply with Quote
Oh, THAT.
Maybe you can machine down the hub a few MM and install an offset 6-bolt sproket WITH the disk brake, with just enough clearacne to run the chain along it?
Might work if you use disk large enough and sprocket small enough. I think Warren did that on his E-cuda

Edited by - Balor on 02/13/2020 06:26:45
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alevand
human power expert

USA
3979 Posts

Posted - 02/13/2020 :  08:36:13  Show Profile  Visit alevand's Homepage  Reply with Quote


http://www.recumbents.com/wisil/jackshaft/jackshaft.htm

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Tony Levand
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warren
human power expert

USA
6770 Posts

Posted - 02/13/2020 :  09:54:37  Show Profile  Visit warren's Homepage  Reply with Quote
I still have this ultra narrow lefty drive FWD front subframe for the Cuda-W which I don't think I am ever going to use. The only time I think about it is when I hit my head on it while walking through the garage.




It uses two custom narrow BBs, a narrow lefty drive hub, 406 wheel and a compact derailleur. It works pretty well but needs tweaking as it's a bit draggy. Make offer if you are interested.

Warren
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warren
human power expert

USA
6770 Posts

Posted - 02/13/2020 :  10:06:25  Show Profile  Visit warren's Homepage  Reply with Quote
The FWD drivetrain on the black lowracer that Tony posted above works great. It's very quiet and shifts nicely. As pictured it handled like the FWD Performer folder that Spidermonkey tested. I lengthened the frame to accommodate the tilting trike unit (Hmm, the tilting unit is also something I am no longer using. hint hint.) and that made it handle much better. It's amazing how much difference in handling a little length behind the seat makes. I don't have a picture of its latest iteration.

Warren

Edited by - warren on 02/13/2020 10:07:01
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