Mountain Bike Reviews Forum banner
1 - 19 of 19 Posts

·
Registered
Joined
·
1,056 Posts
Discussion Starter · #1 ·

·
Registered
Joined
·
9,754 Posts
Bottom bracket drop is the characteristic of the frame that contributes (or not) to pedal strikes. Frames with the same BB drop will have the BB at the same height with the same wheels and tires.
 

·
Registered
Joined
·
2,634 Posts
Next order of business would be suspension design.
If suspension is less active during pedaling, for example, you'll have less strike potential as you're not drooping the bike as often.

Most of mine come from a turn when I am pedaling through and get a bit of bob when a rock is near. Oops. It's more often than I like, but it's not something I'd consider a problem of mine.
 

·
Registered
Joined
·
906 Posts
Looks like the Hightower has a 27 mm drop with the flip chip in the 'high' position: https://www.santacruzbicycles.com/f...-_flip_chip_-_hightower_and_tallboy_final.pdf

Don't think 3 mm is going to make a huge difference either way.

Also the Hightower is due for an update, so buying now may not be ideal. Might be a newer better one and good deals on this one soon.

Have you considered an ibis, a pivot, or a Guerrilla Gravity Smash? They have somewhat higher BBs than the SC stuff.
 

·
Wanna ride bikes?
Joined
·
9,828 Posts
These are both 29ers, why did you post in the plus forum?

I've read a few comments on the Hightower being a pedal strike machine and Trek Fuel Ex not being one ...

I've looked at the Geo in XXL - What am I missing that makes this true? I don't see it ...

Trek Fuel Ex - XXL https://www.trekbikes.com/us/en_US/...el-ex/fuel-ex-8-29/p/23593/?colorCode=reddark

SC Hightower -
XXL
https://www.santacruzbicycles.com/en-US/hightower
Crank length, tire size/volume/rim width, suspension setup/design, lots of variables as has been pointed out. 33mm of BB drop on a full suspension bike is pretty common. Shorter cranks are the quickest/easiest way to help a low BB situation, but it comes at the expense of a higher COG.

BB drop isn't everything. My Surly Krampus has a lot of BB drop (65mm) but still has excellent crank/pedal clearance thanks to the 29x3" tires.
 

·
Registered
Joined
·
64 Posts
The suspension activity also contributes to BB Height. The trek's action is much different than the Hightower.

While I have ridden only the HT, I have friends in my group I ride with regularly which have these bikes. The trek is constantly striking pedals/bash guard. The HT much less frequent.

I notice when observing these bikes that the HT has a much firmer pedaling platform than the trek.

While I agree BB height makes a difference, I do feel that Suspension may have a larger factor than most people believe.

My suggestion, which other will agree, try and demo each bike and see which one suits your riding style the best.
 

·
Registered
Joined
·
27 Posts
I've read a few comments on the Hightower being a pedal strike machine and Trek Fuel Ex not being one ...

I've looked at the Geo in XXL - What am I missing that makes this true? I don't see it ...

Trek Fuel Ex - XXL https://www.trekbikes.com/us/en_US/...el-ex/fuel-ex-8-29/p/23593/?colorCode=reddark

SC Hightower -
XXL
https://www.santacruzbicycles.com/en-US/hightower
Simply put you've heard wrong. It's the other way around.

I couldn't wait to get off the EX.

Sent from my iPad using Tapatalk
 

·
Registered
Joined
·
3,702 Posts
Short cranks are not as long, you foot/pedal stroke doesn't go as low, and you need to raise your saddle.
Shorter cranks aren't as long? :eekster:

Rider COG when seated will be a tad higher, but the difference would likely be negligible. I'm not sure seated COG matters a ton, at least not enough to outweigh the potential benefits of a shorter crank.
 

·
PoDaddy
Joined
·
176 Posts
There is more to it than that. To corner properly (and at speed) without a berm, you want to keep your outside pedal down, correct?
The purpose of this is to lower your CoG as much as possible but also to weight the outside of your tires, primarily your front.

Imagine your bike leaned over in a corner. With shorter cranks, you cannot place your weight, and therefore your CoG, as far to the outside and down (via your outside pedal) as you can with a longer crank. In the corner, your cranks are your counterweight, lever, and weight bearing platforms all at once. A few mm can impact your CoG quite a bit in a corner, which is when it happens to matter the most.

Someone drew a simple diagram of what I'm explaining somewhere on this site before, but I have no idea how to find it.
 

·
Hitching a ride
Joined
·
3,193 Posts
Shorter cranks aren't as long? :eekster:

Rider COG when seated will be a tad higher, but the difference would likely be negligible. I'm not sure seated COG matters a ton, at least not enough to outweigh the potential benefits of a shorter crank.
You ask a simple minded question, so he spoon feeds you the logic so you can follow, and your response is to mock him?
 

·
Registered
Joined
·
3,702 Posts
There is more to it than that. To corner properly (and at speed) without a berm, you want to keep your outside pedal down, correct?
The purpose of this is to lower your CoG as much as possible but also to weight the outside of your tires, primarily your front.

Imagine your bike leaned over in a corner. With shorter cranks, you cannot place your weight, and therefore your CoG, as far to the outside and down (via your outside pedal) as you can with a longer crank. In the corner, your cranks are your counterweight, lever, and weight bearing platforms all at once. A few mm can impact your CoG quite a bit in a corner, which is when it happens to matter the most.

Someone drew a simple diagram of what I'm explaining somewhere on this site before, but I have no idea how to find it.
You may be right, but my bet is that the difference wouldn't really be noticeable. The more dynamic your motion through a turn, the less noticeable it would be. Most people who move to shorter cranks seem to like them. One advantage would be being able to have your feet closer together, which would give you slightly better ROM. Even 1cm can make a difference if your hamstrings are tight. This would allow you to get your COG lower when standing.
 

·
Premium Member
Joined
·
10,753 Posts
You may be right, but my bet is that the difference wouldn't really be noticeable. The more dynamic your motion through a turn, the less noticeable it would be. Most people who move to shorter cranks seem to like them. One advantage would be being able to have your feet closer together, which would give you slightly better ROM. Even 1cm can make a difference if your hamstrings are tight. This would allow you to get your COG lower when standing.
Yup, short cranks have a negligible impact on COG as you can drop you body just as low with long or short cranks, foot position does not determine COG.

Shorter cranks will make a difference in terms of pedal clearance, going from a 175mm crank to a 165mm crank will net nearly 1/2". Also worth looking at pedal thickness and width.

I ride 165mm cranks on all my bikes, they work great, it makes rock strikes far less likely, a great option for "fixing" a bike with an overly low BB.

Another option is to over fork the bike, increase 10mm to get ~5mm additional BB height.
 

·
Premium Member
Joined
·
10,753 Posts
Short cranks are not as long, you foot/pedal stroke doesn't go as low, and you need to raise your saddle.
If you're riding along and suffering pedal strikes, odds are the COG is a non issue because you are either:

1) pedaling seated, which means you are relatively upright and and not riding in a way that COG is a significant issue.

2) pedaling out of the seat, which means you are able to height move your body in a way that allows adjustment of your COG, so crank length again do not matter.

So yeah, a non issue.
 
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top