crandress 

Hello everyone, not exactly C&V except for the frame. I tired the Clydesdale forum first, but got no response. I am upgrading my mountain bike components (Bridgestone BM-3) and looking at Shimano's 3x9 Alivio. However, they make two models of 3x9 cranks. One uses a square taper bottom bracket, the other uses outboard or through bottom brackets, not sure the exact terminology. I am pretty heavy rider, 250+, so is on of these technologies better for a heavy rider? My gut says the square taper is better, but that is without any technical knowledge of the two. So which is better for a heavy rider? If my current bottom bracket is the right length for the 9 speed square taper, I might just go that route, but if I have change it, this would be helpful. Note, I had to upgrade the rims a while back, so the rear hub can do 7-10 speed, so that won't be an issue.

Thanks in advance! Chris

orangeology

i'm no MTB expert, but in general:

1. modern BB = larger spindle + thinner wall = requiring more material/mess in the crank arms i.e) carbon crankset friendly. so your question can also depend on what crankset you have or plan to have.
2. not sure about its relevancy to the rider's weight, but square taper has another advantage of seviceability + relatively more flexibility on chainline adjustment (also due to slightly better interchangeability withing the parts)
3. MB-3 came with Deore which is ok-to-mediocre, ppl seem to keen on to upgrade to XLS or XT.
4. if square taper, i'd go with slightly more modern like with sealed bearings. heard White Industries (come with for 68mm or 73mm shell) make indestructible ones. pricey, but worthy.

good luck and pls post some pics when done. vintage Bridgestones are beauts.

tyrion

Not sure which kind of BB would be considered stronger, but both will be strong enough. Given the choice, I'd go with external - easier to work on and better parts availability (I think).

NatusEstInSuht

Given these two options, I'd go with the Hollowpoint outboard bottom bracket all day long. It will be stiffer and much easier to service.

Road Fan

The best BB is first of all, the one that fits. Second of all, it's one that is available, including its tools, those that you might not have. Third, it's one that is affordable. I think square versus external is not a significant point. Within types there is some hype, maybe a lot of hype, over which brand and level is "most durable" but for every BB there is somebody or several somebodies whom have broken it or had some problem with it resulting in dissatisfaction, regardless of price. Some premium performance aspects, such as smoothness, are just not easy to appreciate on the road, beyond a basic decent level of refinement.

Bigbus

I would go with a square taper and sealed cartridge only because that's what I have on all my current bikes (after upgrading some old loose bearing BBs) and I have all the necessary tools for doing my own work on them. Except that after I upgrade I rarely have to work on them. But do your own research and form your own opinion before you make the leap and you'll probably be happy either way you go.

Narhay

Outboard BB

Classtime 

It looks like you have bikes with loose ball square staper cranks and probably know how to service them. I'd stick with what you know. Whichever you choose, Bottom brackets should not be consumables.

mstateglfr 

Neither is 'better'. They are just different ways to skin a cat.
I tore down a road bike of mine that has a Tange square taper cartridge bottom bracket from a few years ago and was mesmerized by how smooth it turned and how little fricton there is when spinning the crank arms.
But that means nothing in terms of what is best because its not like external bottom bracket cups that don't spin as long are worse.

If updating a ceank to something modern, I would go for an outboard bottom bracket for sure. The overall setup is lighter and stiffer than any square taper setup I've used. Its also dead easy to set up and replace(years later when its needed).

I dont have interest in pulling bottom brackets and fudging with the tension for loose ball bottom brackets. I've done dozens of em, they can work great, but it just isn't an interest.

The tool to remove a Shimano external bottom bracket cup is 10x more secure and easier to use than the tool for a cartridge bottom bracket.

Bigbus

https://www.bikeradar.com/advice/buy...ket-standards/

Just a little help with your research.

crandress 

Thanks for all your responses. Sounds like I am good either way. I am comfortable with adjusting and older square taper or cartridge. I was just mostly concerned if these newer ones would support the weight and it sounds like it does.

Thanks - Chris

Andy_K 

An outboard bottom bracket gives you fixed chainline, with very little you can do to change it. With recent MTB triple cranksets, that's usually 50mm. That's a bit further out than is ideal for a bike with even 130mm rear spacing. The square taper would give you the freedom to choose different spindle lengths to adjust the chainline. This isn't a major issue, but if you've got nothing else tipping the scales, this could be it.

crandress 

Fair point!

Dylansbob 

As a side bar.

As long as you continue to look at Shimano outboard bearing cranks, you'll be fine. I wouldn't recomend FSAs cranks/bbs. That being said, if a 1x appeals to you. I'm pleasantly surprised by the cheap mtb cranks on amazon. There's a few "labels", but they're all the same. Don't forget to check their "Warehouse", return/used ones.