Difficulty getting high quality 7 speed gear?

[Sunder]

I've been looking around lately for parts for a new build. The motors I'm considering all accept only up to a 7 speed freewheeling cluster.

I don't have a problem with that, since I know with electric assist, I don't need that many gears... But have you tried to get good quality parts for a seven speed?

I wanted some good Shimano Brifters. best I could get was some EF51s for $28 delivered. Wanted a new crank set. All the light ones that I'm willing to pay $150 for, are for 9 and 10 speed chains.

So what are other people doing for good quality light weight parts? or do people just not care? like what's another couple kilos and smoother operation on a bike that's barely pedalled?

 

[dogman dan]

Part of why my commuter is front hub. Opens a whole different can of worms though, if you want suspension forks.

I've been able to scrounge semi decent, but not light 7 speed chain cranks by buying up dead partial bikes at the flea. Vintage Mtb stuff from back when it was still 7 speed. Light has never been the issue with me, but I did need better than the tin foil thin wallbike cranks for some of my secondary ebikes. So I'd find an old Trek or whatever, and get at least a stronger crank off it. Usually still the riveted junk, but at least not so likely to warp the chainring.

I don't see why it would be that big a problem though, to run 7 speed chain on 9 speed chainrings. You might have to add some different spacers. I know, likely to wear it out sitting on the ring crooked.

What's this for? Maybe you need a keppler friction drive so you get to leave the bike stock.

There are some new model clyte motors that take a cassete.

 

[MadRhino]

So what are other people doing for good quality light weight parts? or do people just not care? like what's another couple kilos and smoother operation on a bike that's barely pedalled?

If you want a stiff light weight freewheel set, you have to make it yourself. A good light weight crank set can be found for 1/8 chain, the chain itself can be found in Ti, but the freewheel has to be custom made and that is a lot of money and time involved.

 

[d8veh]

7 speed free-wheel gears are pretty easy to come by, but for an electric bike, you need one with an 11T top gear, otherwise you won't be able to pedal fast enough. They're much more difficult to find, but you can get them from here:
http://ebikes.ca/store/store_ezee.php
or in the UK here:
http://www.cyclezee.com/shop.html

 

[Sacman]

I've been looking around lately for parts for a new build. The motors I'm considering all accept only up to a 7 speed freewheeling cluster.

A lot of guys out here (including me and now you) are putting electric motors on newer bikes that have a 9-speed or 10-speed on the rear wheel. The width of the hubmotors on the axles have made this a problem for years. 7-speed freewheels is what most will allow you to fit with not modifications these days. You can get away with 8-speed freewheels but that requires putting washers between the shoulder of the axle and the frame so the freewheel spins clear of the frame. And like already mentioned above, get a 7-speed freewheel with a small 11t chainring so better able to ride at 30+ mph and not have to spin your pedals so fast.

I've been looking around lately for parts for a new build.

I wanted a new crank set. All the light ones that I'm willing to pay $150 for, are for 9 and 10 speed chains.

The problem with this is a 7-speed chain is slightly wider than a 9 or 10-speed chain and therefore will not sit squarely on a 9 or 10-speed chainring and you'll end up getting a little chatter when you pedal. You will see the chain will wear out faster too. I guess if you don't pedal that much it shouldn't matter too much. But I'm a guy who does like to pedal a lot and so I just learned to live with the chain chatter and watch the wear.

That said I do use road crank sets with 9-speed chainrings on them. Sometimes it could be a challenge to fit such a large chainring on and still clear the chainstays on the bike frame. I've found and used older Shimano 105 road crank sets with 52t & 40t chainrings to work well on a couple of my e-mountain bikes. They're discontinued so they don't cost much ($42) but they do need the special bottom bracket ($38) with the special Octalink splines instead of the traditional square ended shaft. Shimano Tiagra road crank sets also work and also come with 53t & 42t chanirings but cost a little more ($89) and will work on regular square ended bottom brackets.

 

[motomech]

I've been looking around lately for parts for a new build. The motors I'm considering all accept only up to a 7 speed freewheeling cluster.

I don't have a problem with that, since I know with electric assist, I don't need that many gears... But have you tried to get good quality parts for a seven speed?

I wanted some good Shimano Brifters. best I could get was some EF51s for $28 delivered. Wanted a new crank set. All the light ones that I'm willing to pay $150 for, are for 9 and 10 speed chains.

So what are other people doing for good quality light weight parts? or do people just not care? like what's another couple kilos and smoother operation on a bike that's barely pedalled?

There is a motor that will accept 9-speed freewheel, but it is a mini, the Cute Q100.
There may be something more powerful in the near future, the much anticipated Bafang BPM CST which will accept a CASSETTE. Up to a 10-speed.

http://endless-sphere.com/forums/viewtopic.php?f=2&t=31624

Some here, have used an 8 or 9-speed crank[chainwheels] and chain on an aftermarket 7-speed freewheel. The rear derailleur is fixed on the 11 tooth cog and the front derailleur is used.

 

[Oakwright]

Shimano makes a nice cheap 7 speed freewheel cluster (hyperglide), however it's 13 teeth (top is 28 teeth). You can find them easily on amazon, but I got my original from sheldon brown / harris cycle.

I have yet to see a decent 11 tooth 7 speed freewheel cluster.

 

[Sacman]

****removed double post*****

 

[Sacman]

Shimano makes a nice cheap 7 speed freewheel cluster (hyperglide), however it's 13 teeth (top is 28 teeth). You can find them easily on amazon, but I got my original from sheldon brown / harris cycle.

I have yet to see a decent 11 tooth 7 speed freewheel cluster.

If money were no object I'd use that Shimano 7-speed freewheel with the 13t and pair it up with a $600 Schlumpf High Speed Drive internally geared crankset with a 24t chainring properly sized for a 7-speed chain. The Schlumpf's 2.5:1 ratio will give an effective 60t chainring at the cranks. That'd give you 60t up front and 13t at the back. You'd have all the gearing to easily pedal up to 40mph with that.

Schlumpf high-speed-drive

http://www.schlumpf.ch/hp/hsd/hsd_engl.htm

 

[Sunder]

This is why I love this forum so much - ask a question that is of no interest to many people, and so many people are still willing to help you out! I didn't realise that parts were a bit more compatible than manufacturers were advertising. Based on your comment, I went to Sheldon Brown's site and read up about chains, and found out that the only difference is the external width of the chain - the internal width and the spacing is the same, so as long as I'm indexing correctly, and the chain isn't so thin it can fit between chainrings, then there's no reason why I can't use a chainring designed for a 9 speed chain at the front, and a 7 speed cluster at the back.

The back story is that I'm 90% power on the way in, and 90% pedal on the way home, due to having no shower at work. So I need a bike that can go 30-35km/h on power only, but can be fully pedaled.

My next build won't be for a while... Well, last year, I did say I was going to do it this year, but now that I'm going on a 6 week trip to Europe, plans will be set back a bit and budget cut a bit for expense reasons. But eventually, I want a a road bike with less than 15kg total weight including battery, a 20km range, and a top speed of around 30km/h without pedaling. It's going to be semi-stealth. Funny, the Q100 was one of the motors I was looking at, but I didn't know it could take a 9 speed. At 350W it's a bit under powered, but I've read it can take 700w for quite a while, and 1kw for a few seconds without problems.

One other thing though, is that I've been challenged to do a triathlon, so pedaling a 30+kg direct drive motor is really going to be good for training, so I'm okay with keeping it for a while - but now want the running gear to be much better quality, since I'm relying on it a lot more.

 

[motomech]

Two builds using the Q100 w/ a 9-speed freewheel,

http://endless-sphere.com/forums/viewtopic.php?f=3&t=32364

A bonus is the wires on the Q100 exit the left[non-chain drive] side.

 

[corkscrew]

Do you have a bicycle co-op in your area? I know the local one here has tons of the old 7 speed stuff.

As far as brifters, I don't think any decent ones are still made new, but I have seen some sora 7 speed brifters on e-bay and in LBS's clearance rack.

You could always go with a mid motor, that would allow you to keep the stock cassette.

 

[manitu]

Most 9-gear cranks with stadard bolt-patterns wil accept a 7-gear chainring.

.manitu

 

[BATFINK]

My problem is with a seven speed cassette on the rear with a mac 8t. If I select the largest cog closest to the motor the rear dérailleur rubs against the outside edge of the motor. The rear drop outs are aluminium and how would I increase space between the cassette and motor?

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[Oakwright]

My problem is with a seven speed cassette on the rear with a mac 8t. If I select the largest cog closest to the motor the rear dérailleur rubs against the outside edge of the motor. The rear drop outs are aluminium and how would I increase space between the cassette and motor?

Not to be pedantic, but it's a cluster, not a cassette. Rear motors use freewheel clusters, not freehub cassettes. I mention this mostly because it would suck to buy the wrong part. http://sheldonbrown.com/freewheels.html

There should be a screw on your derailleur for low stop. If you tighten that up a bit, it should keep it from bumping against the motor. However, that probably also will keep the chain from getting onto the gear. So, what you can do is put a spacer between the cluster and the motor. Take the cluster off, and just drop a washer right onto the axle. I had to do that on both of my bikes in order to keep the cluster form rubbing against the motor when coasting, so I'm sure you could use the same thing to add a little more space. The washer I used which has worked fine for several hundred miles is 1 1/8 inch outer diameter, 5/8 inch inner diameter I think.

If you add too much spacing though, then your cluster will rub against your frame.

 

[BATFINK]

Thanks Oakwright, il give it a try as it would be nice to have the gears nice tip

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[Kirk]

Harris Cyclery (Sheldon) has some nice shifters and brifters http://sheldonbrown.com/harris/shifters.html

ebike has some nice freewheel gear clusters, both 11-28T and 11-34T 7 speed clusters http://ebikes.ca/store/store_motors.php