Keiser M3 - help resolving a few issues

[wheelerman]

Hello, I recently received a Keiser M3 as a hand-me-down. Definitely not a bike I could afford to buy and it's in pretty rough shape, but I couldn't pass this up. I'd like to resolve a few of issues and I don't mind getting my hands dirty. You'll have to forgive me for not knowing the correct nomenclature.

(1) After about a total of 4 hours of use, I noticed that the assembly that includes the right crank, the pulley, and the left crank will "shift" out of alignment slightly when pedaling under resistance. So I used my hands to try and isolate the issue and what I found is that if you look down at the pulley from above (imagine you're in a forward facing seated position and look down at the pulley), from this perspective the pulley is susceptible to rotating slightly counter-clockwise when force is exerted on the pedals. (So the half of the pulley that is closest to the front of the bike shifts in/left, and the rear half shifts out/right) When pedaling the pulley thus moves out of alignment when the right foot pushes down on its pedal, and it shifts back and returns to its "idle" position as the left foot pushes down on its pedal. However, note that from the downward facing perspective the counter-clockwise rotational movement that the pulley is susceptible to is independent of the orientation of the pedals: the front half always shifts in/left and the rear half out/right.

(2) When pedaling the bike is noisier than I expected it to be but still tolerable. It sort of sounds like very muted revving of a car's engine.

(3) There is some rust around the bolts and bolt holes that secure the main frame to the frame base. What would be the best way to remove this rust? And should I completely disassemble the bike and remove all rust I can find?

Thanks

[Stasher1]

It's common for used spin bikes from commercial settings to be due for at least a partial rebuild, if not a complete tear-down. At a minimum, i'd be looking into a replacement bottom bracket and belt.

They always seem like such a bargain, but the cost of repair parts can easily exceed the resale value of even the nicest indoor cycle, and don't even get me started on the cosmetics. These things get covered in sweat during every class and they're rarely cleaned completely, so they all have some level of rust/corrosion.

I picked up a pair of Schwinn IC Elite spin bikes a couple weeks ago for $50. I built one complete bike out of the two and sold it for $170. I'm currently rebuilding the second one, and it has rapidly eaten up all of the profits from the first bike.

[Stasher1]

If you need parts, Sportsmith seems to have a pretty good selection of M3 parts.


http://www.sportsmith.net


I've ordered from them a couple times now with no complaints.

[wheelerman]

If you need parts, Sportsmith seems to have a pretty good selection of M3 parts.


sportsmith


I've ordered from them a couple times now with no complaints.

Thanks for the quick reply! I was actually just looking at sportsmith when I saw your response. I downloaded the exploded view of the M3 and it's looking like the Bottom Bracket (which I've come to understand to be the axle and the two bearings) can only be purchased as a set with the right crank arm--is this correct? Can't the direct link to the right crank arm due to forum limitations.

However, I see bearings on eBay that have the same model number (6004ZZ) as the Keiser ones, but they're being used in some high-end RC car instead and you get 2x for $6.85 instead of 2x for $22.80. (titled "6004ZZ (20x42x12 mm) Metal Shielded High Precision Ball Bearing") If these will work (I'm not sure if the 6004ZZ # guarantees they're the same) then I'd just have to find an axle.

Also, what do you use to remove the rust from the bikes you refurbish?

EDIT: Oh and one more thing: do you think I'll be able to replace the bottom bracket on the M3 without one of those bottom bracket tools?

[Stasher1]

Thanks for the quick reply! I was actually just looking at sportsmith when I saw your response. I downloaded the exploded view of the M3 and it's looking like the Bottom Bracket (which I've come to understand to be the axle and the two bearings) can only be purchased as a set with the right crank arm--is this correct? Can't the direct link to the right crank arm due to forum limitations.

However, I see bearings on eBay that have the same model number (6004ZZ) as the Keiser ones, but they're being used in some high-end RC car instead and you get 2x for $6.85 instead of 2x for $22.80. (titled "6004ZZ (20x42x12 mm) Metal Shielded High Precision Ball Bearing") If these will work (I'm not sure if the 6004ZZ # guarantees they're the same) then I'd just have to find an axle.

Also, what do you use to remove the rust from the bikes you refurbish?

EDIT: Oh and one more thing: do you think I'll be able to replace the bottom bracket on the M3 without one of those bottom bracket tools?

If you know the bearing size, I don't see any reason why you couldn't just replace the bearings in the bottom bracket and reuse the shaft...as long as you don't damage it or break the crank arm bolt off when your try to remove it.

Never worked on a Keiser so I don't know if you can get the bottom bracket out without a crank arm puller and bottom bracket tool, but I'd bet money that you'll need at least the bottom bracket tool. You may be able to simply pop the crank arm off with a deadblow hammer...but I wouldn't count on it.

Like I said before, the price is tempting when you look at used spin bikes, but the cost of parts/tools/supplies will add up quickly.

[wheelerman]

If you know the bearing size, I don't see any reason why you couldn't just replace the bearings in the bottom bracket and reuse the shaft...as long as you don't damage it or break the crank arm bolt off when your try to remove it.

Never worked on a Keiser so I don't know if you can get the bottom bracket out without a crank arm puller and bottom bracket tool, but I'd bet money that you'll need at least the bottom bracket tool. You may be able to simply pop the crank arm off with a deadblow hammer...but I wouldn't count on it.

Like I said before, the price is tempting when you look at used spin bikes, but the cost of parts/tools/supplies will add up quickly.

I was looking at the Keiser M3 service manual. It describes the replacement of the bearings and the axle in detail. A bottom bracket tool is not mentioned (instead a hammer is used), but a crank arm puller is required. They mention the Keiser PN 505428. However, I cannot find this part anywhere. Do you know if any crank arm puller will work? Are crank arms and crank arm pullers standardized?

Thanks

[Stasher1]

This video might help some...

[wheelerman]

Was finally able to put some more time into this. I've successfully removed the bearings and the axle. I used a "Park CCP-22 Cotterless Crank Extractor" on the Keiser M3 and as far as I can tell it worked fine. Sportsmith wanted almost $30 (incl shipping) for the crank extractor they recommended but the Park brand crank extractor only cost me $10.

And yeah, those bearings were shot. Here's one of them (can't post images/links, but I don't see anything wrong with just providing the imgur image IDs): imgur pJUP0Rh

Here's the axel/shaft (uncleaned). I plan to try and use it again: imgur NSgNZVM

And here's a comparison of the bearings I bought on eBay (bottom of picture) vs the "official" Keiser M3 bearings that came out of the bike (top of picture, this one's in better shape than the other pictured above): imgur bAqcNUT

It may not look it, but they have the same inner and outer diameters. But they differ with respect to the thickness of the inner and outter "cyllinders". Not sure if this will affect things but they fit just fine. I bought these off of eBay because the cheapest I could find for the "official" bearings was $11.40 per bearing + $10.25 shipping (so $33.05 for two bearings...), so I won't be too upset if this $7 pair of bearings from ebay doesn't pan out. Actually, the "official" bearings displayed on sportsmith look more like the bearings I bought on eBay because--unlike the bearings which came out of my bike--the inner cyllinder is thinner than the outter cyllinder.

So now, according to the manual, I need to purchase 3 different grades of Loctite (242,638,680)--about $5 each--and two "hose spacers" (part # 543091)--only $1.50 each but again sportsmith kills you with the shipping costs so $15. If only I could find these "hose spacers" elsewhere...


So far my costs are:
$10 - crank extractor
$6.85 - pair of 6004ZZ bearings off of ebay
$15 - loctite 242,638,680
$15 - hose spacer long (part # 543091)
___
$46.85

You weren't kidding. Even when you're pinching pennies like I am, things really start to add up.

[Stasher1]

Was finally able to put some more time into this. I've successfully removed the bearings and the axle. I used a "Park CCP-22 Cotterless Crank Extractor" on the Keiser M3 and as far as I can tell it worked fine. Sportsmith wanted almost $30 (incl shipping) for the crank extractor they recommended but the Park brand crank extractor only cost me $10.

And yeah, those bearings were shot. Here's one of them (can't post images/links, but I don't see anything wrong with just providing the imgur image IDs): http://m.imgur.com/pJUP0Rh

Here's the axel/shaft (uncleaned). I plan to try and use it again: http://m.imgur.com/NSgNZVM

And here's a comparison of the bearings I bought on eBay (bottom of picture) vs the "official" Keiser M3 bearings that came out of the bike (top of picture, this one's in better shape than the other pictured above): http://m.imgur.com/bAqcNUT

It may not look it, but they have the same inner and outer diameters. But they differ with respect to the thickness of the inner and outter "cyllinders". Not sure if this will affect things but they fit just fine. I bought these off of eBay because the cheapest I could find for the "official" bearings was $11.40 per bearing + $10.25 shipping (so $33.05 for two bearings...), so I won't be too upset if this $7 pair of bearings from ebay doesn't pan out. Actually, the "official" bearings displayed on sportsmith look more like the bearings I bought on eBay because--unlike the bearings which came out of my bike--the inner cyllinder is thinner than the outter cyllinder.

So now, according to the manual, I need to purchase 3 different grades of Loctite (242,638,680)--about $5 each--and two "hose spacers" (part # 543091)--only $1.50 each but again sportsmith kills you with the shipping costs so $15. If only I could find these "hose spacers" elsewhere...


So far my costs are:
$10 - crank extractor
$6.85 - pair of 6004ZZ bearings off of ebay
$15 - loctite 242,638,680
$15 - hose spacer long (part # 543091)
___
$46.85

You weren't kidding. Even when you're pinching pennies like I am, things really start to add up.

Fixed your links.

Good work on the bike. I'm glad to see you decided to fix it and restore it to proper function.

[wheelerman]

Fixed your links.

Good work on the bike. I'm glad to see you decided to fix it and restore it to proper function.

Thanks for the support along the way. I gave it my first test run tonight and it works great. I ended up completely disassembling the bike, cleaning it, removing the rust from everything by soaking various pieces in vinegar and scrubbing them with a wire brush, repainting it (not the same color, just rustoleom to prevent rust), and then reassembling everything. Only thing I might do in the future is replace the bearings on the flywheel and idler (6203Z and 203KDD respectively) as that part of the bike is still a little noisey.

Will let you know if I run into any issues. By the way, when re-assembling the bottom bracket I had difficulty simultaneously getting the shaft and bearings (with loctite applied) to stay put while attaching the crank arms. If I had bought the right crank arm assembly (which includes the right crank arm, rubber spacer, right bearing, and shaft) as one piece it would have been easy. But in my case everything was separate, and during assembly either the bearings and shaft would dislodge, or the crank arms would ultimately end up having a bit of lateral give even after tightening the crank-arm<->shaft bolts.

So, despite the manual saying specifically not to do the following, I ended up applying the loctite to the properly set bearings and shaft alone in the bottom bracket housing. Next I took two large washers and put them over each end of the shaft, set them flush up against the bearings, and then used 2 clamps to hold them tight up against the bearings for 24 hours (while the loctite dried). After that, I gently put both crank arms on and carefully tightened them simultaneously.

I suppose another way to do it would have been to first put together the right crank arm assembly, use a rubber mallet to bang the shaft tight into the right crank, let it dry for 24 hours, and then put it together as specified in the service manual. But then I'd be waiting 24 hours for each of the two loctite applications...

[Phillmax]

Folks I stumbled across this thread, so if your needing to fix the main crank bearings. Here is what you need and what it costs.

2 x koyo 6004z bearings or equivalent. I bought skf 6004z from ebay for £2.76 each.

1 x Park Tool CCP-22 Cotterless Crank Puller Tool from amazon at £13.

14 mm socket and ratchet.

Hammer and straight screwdriver.

Steps

Remove the plastic caps on the pedal arm, remove 14mm bolt. Use the crank puller tool to remove the arms. Use hammer to gently tap out the square crank arm. Remove the two bearings by tapping them with a screwdriver and hammer. Then rebuild. Job done in 20 minutes. Pedal clunk gone for £20.

[Danomarco]

Thanks for the support along the way. I gave it my first test run tonight and it works great. I ended up completely disassembling the bike, cleaning it, removing the rust from everything by soaking various pieces in vinegar and scrubbing them with a wire brush, repainting it (not the same color, just rustoleom to prevent rust), and then reassembling everything. Only thing I might do in the future is replace the bearings on the flywheel and idler (6203Z and 203KDD respectively) as that part of the bike is still a little noisey.

Will let you know if I run into any issues. By the way, when re-assembling the bottom bracket I had difficulty simultaneously getting the shaft and bearings (with loctite applied) to stay put while attaching the crank arms. If I had bought the right crank arm assembly (which includes the right crank arm, rubber spacer, right bearing, and shaft) as one piece it would have been easy. But in my case everything was separate, and during assembly either the bearings and shaft would dislodge, or the crank arms would ultimately end up having a bit of lateral give even after tightening the crank-arm<->shaft bolts.

So, despite the manual saying specifically not to do the following, I ended up applying the loctite to the properly set bearings and shaft alone in the bottom bracket housing. Next I took two large washers and put them over each end of the shaft, set them flush up against the bearings, and then used 2 clamps to hold them tight up against the bearings for 24 hours (while the loctite dried). After that, I gently put both crank arms on and carefully tightened them simultaneously.

I suppose another way to do it would have been to first put together the right crank arm assembly, use a rubber mallet to bang the shaft tight into the right crank, let it dry for 24 hours, and then put it together as specified in the service manual. But then I'd be waiting 24 hours for each of the two loctite applications...

Hi @wheelerman

I'm currently in the process of reassembling my M3, basically doing what you've reported above. I want to re-purpose the axle since the right crank is still sound, so what I tried first before using loctite to secure the axle and bearings, is re-assemble the parts and gently pedal. I noticed there is a slight wobble (left to right) in the large pulley and I'm trying to figure what may be causing this. During the disassembly process, I did end up having to give the axle end a few hard whacks to dislodge it. I've rolled it on a flat surface and it looks good. I've set down the large pulley on a flight surface and is ok. Any thoughts? I'm trying to mitigate securing it in there then having to remove it again if something's wrong after the loctite has set.

Note to self: rehabilitating a used M3 isn't always the wisest decision. :-|