Mechanics Quick Question Thread [Ask Questions Here]

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Mechanics Quick Question Thread [Ask Questions Here]
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flag naptime
Posted: Mar 7, 2021 at 23:18 Quote
(I think) that could ease the twitchy'ness but, you'll definitely still feel some. maybe add 10mm or so to bar width if it's detrimental?
flag R-M-R
Posted: Mar 7, 2021 at 23:21 Quote
The shorter offset will produce more steering stability at speed, not less.

The difference isn't huge. Few people can even notice 5 mm of change in offset, so it's not like 8 mm will be a huge difference.

With seat-tube angles getting so steep - as they should! - I'm a fan of very long reach combined with moderate head-tube angles and short offset. This keeps the maintains steering trail without the front-centre getting too long.
flag erdinc
Posted: Mar 7, 2021 at 23:24 Quote
I will be putting the fork to a 2017 bike so geometry is traditional, can it effect it more compared to a modern bike?
flag R-M-R
Posted: Mar 7, 2021 at 23:30 Quote
Assuming the travel and axle-to-crown length are the same as the original fork, the difference will be ~7 mm more trail and ~7 mm less front-centre length. The changes, all of which are slight:

• Greater stability at high-speed
• Greater wheel flop at low speed (tendency for the front wheel to flop to the side)
• Less front-centre length, which slightly increases the likelihood of going over the front
flag mrgonzo
Posted: Mar 8, 2021 at 6:36 Quote
R-M-R wrote:
I think johnovey is on the right track. I would take the same approach and cut whatever notch I could into the nut, then hit it with a punch. The notch could be cut with a tiny, dental-style cutting tool on a high-speed drill, if you want to salvage the chainring. If you can live with cutting into the chainring, a thin cut-off wheel on the high-speed drill will make a suitable notch, likely also cutting into the 'ring along the way.

Thanks rmr and bonjovey I'll try to pick up a cutting tool for the drill.
flag adespotoskyli
Posted: Mar 8, 2021 at 7:59 Quote
Noeserd wrote:
What could go wrong if i use 38mm instead of 46mm fork offset for a bike designed around 46
more wheel flop at slow speeds but less prone to trail input at high speeds ie more stable. There isn't a bike designed around a certain amount of offset. Offset is standard in the industry, it's a new concept used by some bike brands to market their bikes but you can use whatever offset you like/find to suit your liking.
flag Flecasaur
Posted: Mar 8, 2021 at 8:04 Quote
Replacing NX Dub cranks with X01 dub cranks, they've arrived with some green/blue gunk on the spindle and some brownish looking stuff in the crank arm.
Is this grease? Is it sufficient?
Haven't seen this on any of the install videos I've watched, should I remove it and replace it with this grease I have?

photo
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larger pictures here https://postimg.cc/gallery/svy0pBm/fa3a606e
Thanks
flag Kidklayko
O+
Posted: Mar 8, 2021 at 9:35 Quote
I have a 2014 5010 and a 2016 Mojo HD3. As of recent, I can't figure something out. I rode the Ibis of recent and I found that it pedaled wayyy better than the 5010. The geometry is similar 73 ST for 5010 and 72.7 ST for the HD3. But I think the Ibis effective ST measures closer to 74.5 and the 5010 is still 73. Why would the Ibis pedal better than the 5010? It weighs 4 lbs more, it has slower rolling tires, it has more travel. It does have a 54T rachet upgrade where the 5010 has an 18T is that the difference? Even out of the saddle it pedals better so I know it's not the ST. The 5010 is an 11 speed and HD3 is an AXS but even when it was an 11 speed it just feels more efficient. Does anyone know why this could be happening?
flag bishopsmike
O+
Posted: Mar 8, 2021 at 9:41 Quote
Kidklayko wrote:
I have a 2014 5010 and a 2016 Mojo HD3. As of recent, I can't figure something out. I rode the Ibis of recent and I found that it pedaled wayyy better than the 5010. The geometry is similar 73 ST for 5010 and 72.7 ST for the HD3. But I think the Ibis effective ST measures closer to 74.5 and the 5010 is still 73. Why would the Ibis pedal better than the 5010? It weighs 4 lbs more, it has slower rolling tires, it has more travel. It does have a 54T rachet upgrade where the 5010 has an 18T is that the difference? Even out of the saddle it pedals better so I know it's not the ST. The 5010 is an 11 speed and HD3 is an AXS but even when it was an 11 speed it just feels more efficient. Does anyone know why this could be happening?

I can't comment on the 5010, but Ibis are known to pedal VERY well, due to the way their dw-link is set up. My 160mm-travel Ibis pedaled much better than my 3 other 140mm-travel bikes I've owned.
flag Kidklayko
O+
Posted: Mar 8, 2021 at 9:43 Quote
Yeah, I know Ibis, Pivots, Evils, and Devinci's are all supposed to pedal really well because they have Dave Weagle designed suspension. But the 5010 still weighs 26.5 lbs and the Mojo HD3 weighs around 30. Even locked out the Ibis feels more efficent
flag freestyIAM
Posted: Mar 8, 2021 at 9:57 Quote
Kidklayko wrote:
I have a 2014 5010 and a 2016 Mojo HD3. As of recent, I can't figure something out. I rode the Ibis of recent and I found that it pedaled wayyy better than the 5010. The geometry is similar 73 ST for 5010 and 72.7 ST for the HD3. But I think the Ibis effective ST measures closer to 74.5 and the 5010 is still 73. Why would the Ibis pedal better than the 5010? It weighs 4 lbs more, it has slower rolling tires, it has more travel. It does have a 54T rachet upgrade where the 5010 has an 18T is that the difference? Even out of the saddle it pedals better so I know it's not the ST. The 5010 is an 11 speed and HD3 is an AXS but even when it was an 11 speed it just feels more efficient. Does anyone know why this could be happening?

Kinematically, Dave designs the DW link bikes to have antisquat above or at 100% through more of the travel than Santa cruz. Take the 2020 Santa Cruz High Tower and the 2020 Ibis Ripley. The Santa cruz has AS above/at 100% through 55 of its 120mm of travel, i.e. 46% of travel. The Ripley on the other hand has its AS above/at 100 through 80 of its 120mm of travel, i.e. 67% of travel. In short, the Ripley has higher AS through more of the travel than the 5010 so you should expect the Ripley to peddle better.

TLDR the Ripley pedals better because it's kinematics were designed to pedal better. If you are ever wondering why one bike has kinematic attributes that differ from another bike, the only way to tell is to review the kinematics.

PS Note there is nothing about the link orientations (counter rotation top link of VPP v corotating link of the DW system) that inherently determines this. Just how the designers choose to design the kinematics.

PPS if we go back in time to the years you are taking about the 2016 Mojo 3 had even higher AS than the 2016 Santa Cruz 5010 through even more of the travel so it makes sense that the peddling efficiency would be that much better
flag gabriel-mission9
Posted: Mar 8, 2021 at 11:15 Quote
mrgonzo wrote:
R-M-R wrote:
I think johnovey is on the right track. I would take the same approach and cut whatever notch I could into the nut, then hit it with a punch. The notch could be cut with a tiny, dental-style cutting tool on a high-speed drill, if you want to salvage the chainring. If you can live with cutting into the chainring, a thin cut-off wheel on the high-speed drill will make a suitable notch, likely also cutting into the 'ring along the way.

Thanks rmr and bonjovey I'll try to pick up a cutting tool for the drill.

Before cutting anything, you still have options!

First of all I would try an impact wrench with an allen key bit. This can work wonders when removing fittings that are just spinning.

If that doesn't work, try heat combined with impact wrench.

If that doesn't work... go to town with the cutting tools
flag freeriderayward
Posted: Mar 8, 2021 at 11:51 Quote
Flecasaur wrote:
Replacing NX Dub cranks with X01 dub cranks, they've arrived with some green/blue gunk on the spindle and some brownish looking stuff in the crank arm.
Is this grease? Is it sufficient?
Haven't seen this on any of the install videos I've watched, should I remove it and replace it with this grease I have?

The grease on crank spindles is only really for ease of installation and removal, it's the grease inside the bottom bracket bearings that provides the lubrication. So you just want a small amount of that. What you have would suffice.

Also, the brown grease is probably copper based anti-seize, which also aids removal down the track. You could wipe away any excess with a paper towel, and the thin layer left would be adequate. Too much grease around these areas will attract grit and grime from riding.
flag masonsmith
O+
Posted: Mar 8, 2021 at 11:53 Quote
This past weekend I broke my rear axle, the threads sheared right off. I believe it was because of a crash. However, after the crash, I was able to ride for a few miles before I noticed it had broken. Did the crash likely cause the axle to break, and is there any way to prevent it from happening in the future?
flag Flecasaur
Posted: Mar 8, 2021 at 12:14 Quote
freeriderayward wrote:
Flecasaur wrote:
Replacing NX Dub cranks with X01 dub cranks, they've arrived with some green/blue gunk on the spindle and some brownish looking stuff in the crank arm.
Is this grease? Is it sufficient?
Haven't seen this on any of the install videos I've watched, should I remove it and replace it with this grease I have?

The grease on crank spindles is only really for ease of installation and removal, it's the grease inside the bottom bracket bearings that provides the lubrication. So you just want a small amount of that. What you have would suffice.

Also, the brown grease is probably copper based anti-seize, which also aids removal down the track. You could wipe away any excess with a paper towel, and the thin layer left would be adequate. Too much grease around these areas will attract grit and grime from riding.
Thanks!
You talked about bottom bracket bearings, I haven't touched the bottom bracket and the bike hasn't had much usage. Do I need to worry about that? I didn't see anything about greasing bottom bracket bearings on the official video https://youtu.be/E0CDaxwbd5c

 


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