Shimano Biopace HP restoration - Retro MTB

[@carlvanderheijden4981]

I recently bought a 1989 Panasonic MC 4500. It felt immediately right but I couldn't put my finger on it what this bike made me feel so good. Than it hit me: the Bio-Pace chainrings! I think it is muscle memory: I started mountain biking in the late 80's on a bike with Bio-Pace. Fast forward: I put them on 3 other bikes I have. For example a Kona Rove gravel bike. Thanks for the video

[@christopherbartleson8918]

Those cranks look amazing, I need to get myself an old set to do this to, looking at a set of Deore XT FC-M739 cranks to do this too and replace the decals as well.

[@red_dread]

Absolutely fantastic. This has highlighted the fact that so many of the builds on my channel are let down by my scruffy cranks! Also great bit of history on the HP name. I wish I'd known that back in the 80s when I was riding Biopace, it would have been another thing to boast about in the playground.

[@ministryoftruth8588]

I have EVERY Tooth Count Shimano Biopace CRs made (in 74bcd: 26 and 28t, 110bcd: 36, 38, 44, 46, 48, and 50t, and 130bcd: 40t [Made of Steel only], 42, 52, and 53t). They're Good for Older Cyclist with Knee Problems and providing MTBs with More Traction while Climbing on Loose Dirt or Gravel. Also you can Climb Hills or Cruise on Flats in a Lower Cadence (~ 2 - 4 rpms less depending on the Size of the CR) w/o effecting Efficiency and Feel at Higher Cadences. The DOWNSIDES with these CRs are you're more likely to Drop your Chain when Shifting the FD AND you need a Higher Capacity FD for Triple Cranks (~ 3 Teeth Higher). As Mentioned in some of the other Comments: You CAN Rotate Biopace CRs and get a Similar Configuration as the More Expensive Modern Oval CRs, whereas the 'Larger Tooth Count' (Larger Diameter of the CR) is Positioned at the 1:00 to 5:00 O'clock 'Power Stroke' Position, tho with Jury Rigging a Biopace CR's Position the Largest Diameter of the CR WON'T be AS IDEALLY Positioned as the Newer Oval CRs are. Keep in Mind Biopace CRs were designed with the SMALLEST Diameter of the CR positioned in the 'Power Stroke' 1:00 - 5:00 O'Clock Position of the CR, and the LARGEST Diameter of the CR in the "Dead Spot" 5:00 - 7:00 O'Clock Position. The IDEA being to 'Speed Up/Minimize' the Exertion in the 'Power Stroke' (Thus REDUCING Muscle Fatigue), AND 'Speed your Legs Up' going into the 'Longer Dead Spot' so as to Compensate for your Legs 'Slowing Down" THRU the LONGER 'Dead Spot' created by the Larger Diameter Design Feature of the Biopace CR (the 'Longer Dead Spot' was Designed to give your Legs MORE 'Rest Time'). Actually the Idea was by INCORPORATING these Features into Biopace CRs, this ALL would make you Cycle FASTER! In THEORY, This was a BRILLIANT and iNGENIOUS Idea on the Part of Shimano, however there's Debate as to WHETHER this ACTUALLY Works to REDUCE Leg Fatigue and Make you Cycle Faster. However Wattage Experiments Conclude You WILL NOT LOSE ANY POWER and You WON'T RIDE SLOWER Riding with Biopace CRs compared to Regular Round CRs. Also I CAN'T FEEL ANY DIFFERENCE btw. Pedaling Biopace and NORMAL ROUND CRs. I REALLY LIKE Biopace CRs, which runs Contrary to how MOST Cyclists feel about them.

[@grumpy_ken]

wow that came out great. I just disassembled a biopace crankset that is looking crusty. I didn't know there were buffing wheels for grinders- I will try one! great vid

[@W1DO]

The buffing wheels on the grinder work better if you don't run them at full speed for too long as they get very hot and stop polishing properly.

[@glipho01]

I Have a 31 years old Biopace..working like the first day. I really love it instead almost all other biker don,t like...I can,t understand why??????...now I want some one for my newer mtb but there,s not with octalink system...😏😩😩

[@W1DO]

You could try a "rotor" or "absolute black" elliptical chainring? Might not be the same feeling (don't think the high/low spots line up with the same crank position when compared with the old biopace) but could be worth a try to see if you like it.

[@disaannecooper-asperin6415]

Omg...I'm still trying to remove the crank..I gave up on the pedals...every job requires a new tool...🤪

[@W1DO]

Cover them in penetrating oil a few times a week and maybe one day they will move... you can always use a blow torch if you get desperate too - just don't melt anything :)

[@daniellarson3068]

That crank looks aluminum. Were the pedals steel? I wonder if there was a dielectric thing that caused the pedals to rust in place. I am planning on going through my old bike I bought in 1991 or 1992 and may have the sane situation. This video gave me a good warning. Yours looked new when you were done.

[@W1DO]

Steel vs aluminum in the damp for decades. I'd say they definitely bonded together. Does look super Shiney and better than new now, think I will get round to finishing the stumpjumper soon!

[@grumpy_ken]

bikes use aluminum on steel all over the place for some reason. aluminum seatposts on old metal frame mtb's was common and by now they have all welded themselves together lol

[@daniellarson3068]

@@grumpy_ken I changed some parts on the old bike and used dielectric grease where steel mated to aluminum. Hopefully, it will prevent that reaction.

[@achn2b]

You don't have to lacquer the cranks after polishing? They won't dull up over time? Those cranks are pretty.

[@W1DO]

I will just be polishing them lightly every time they look a bit tarnished.

[@stinkyfinn6977]

The shimano biopace work much better if you move the peak of the oval so it about 45degree to the peddle arms ,

[@W1DO]

Yes, I saw some articles on that, I think I will try it in standard configuration first then switch it round and see if I can tell the difference :)

[@stinkyfinn6977]

@@W1DO Apparently shimano bio pace is 60 degrees or so out according to modern study's, I changed mine and I definitely felt like I get more out of them , mine are suggino cyclone on a 5 leg crank so basically the same as the bio pace , would love to hear your thoughts when you change your set up