Need help picking a new fork and with geometry

MarkJohnston

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Mar 25, 2021
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620
Hi,

I have a problem with my current bike. I have a powerful hope tech downhill mtb brake on it The problem is that the fork is pulled to one side when using it, the stanchions are only 32 mm at their widest point. this fork is cheap and FLEXES like crazy, it is one of those zoom forks btw. The stanchions on downhill bikes are massive. The only problem is my current frame is designed to only have 60 mm (or so not really sure the fork says MX-60 )of travel, but these downhill forks all have 200 mm travel.

I've been searching pinkbike.com, craigslist.org, ebay.com for the correct fork but have not found anything with heavy duty stanchions or something that is up to task. It seems like I would need to buy a new 26 inch wheel with a through axle but even that would be difficult to find because 26 inch is going out of style like a bat out of hell. I mean, it's almost to the point where I feel like I should retire this bike because the aluminum could be fatiguing and micro fracturing, I ride like a mad man with tons of cargo.

Does anybody have an ideas or have any experience putting a massive 100 mm of travel on a bike not meant for it? will it be something similar to a dutch bike where you sit upright? I have done tons of research on this but haven't really figured anything out yet.

HEre is a link to the bike I have of course I have customized the s H i t out of it lol, but the fork is still stock.

https://www.bikesdirect.com/products/motobecane/mountain_bikes/300ht-mountain-bikes.htm
 
I've seen people put bigger front wheels than their back wheels, in case that opens up some options for you.
 
MarkJohnston said:
I have a problem with my current bike. I have a powerful hope tech downhill mtb brake on it The problem is that the fork is pulled to one side when using it, the stanchions are only 32 mm at their widest point. this fork is cheap and FLEXES like crazy, it is one of those zoom forks btw.

Does anybody have an ideas or have any experience putting a massive 100 mm of travel on a bike not meant for it? will it be something similar to a dutch bike where you sit upright? I have done tons of research on this but haven't really figured anything out yet.


Doesn't really matter how powerful your brake is; almost any disc brake is able to lock up the wheel. That fork is ridiculously cheap if it twists under braking, or it's in serious need of a rebuild.

Buy a name brand fork and you should be fine. They have a reputation to maintain, so even their lower line models shouldn't twist under braking. A laxed head tube angle provides more high speed stability. If the bike is designed for pedaling speeds, but it going ebike speeds, the added stability might be desired.

I used a Fox Talas for a while, which has adjustable travel (100mm-140mm) and now use a Fox Vanilla 160mm. The longer travel works great; no handling issues. The shortest travel made the bike more twitchy.
 
I have an older Rockshox Revelation fork with 32mm stanchions and when I changed it's travel from 120mm to 150mm it started to flex noticeably. Increasing the travel on that bike worked otherwise really well, especially as I could also make the wheelbase a bit longer with adjustable dropouts (Kona Honzo).

Newer Revelation on another bike has 35mm stanchions and it is clearly more stiff at 150mm travel. I would think that up to 100mm the 32mm diameter should be enough with a reputable brand forks but with longer travel I would get at least 35-36mm stanchions.
 
I had the same problem with the wheel pulling to one side under braking.

Turns out a generic quick release skewer is much weaker and poor quality, replacing it with a genuine Shimano one and tightening it fixed the problem significantly.

With regards to replacing the forks, you need to check if it’s taper or straight steerer. The amount of travel could vary but you need to get approx the same axle to crown height.

If there’s a rebound setting on your current forks try turning it up to max for the extra weight.
 
E-HP said:
MarkJohnston said:
I have a problem with my current bike. I have a powerful hope tech downhill mtb brake on it The problem is that the fork is pulled to one side when using it, the stanchions are only 32 mm at their widest point. this fork is cheap and FLEXES like crazy, it is one of those zoom forks btw.

Does anybody have an ideas or have any experience putting a massive 100 mm of travel on a bike not meant for it? will it be something similar to a dutch bike where you sit upright? I have done tons of research on this but haven't really figured anything out yet.


Doesn't really matter how powerful your brake is; almost any disc brake is able to lock up the wheel. That fork is ridiculously cheap if it twists under braking, or it's in serious need of a rebuild.

Buy a name brand fork and you should be fine. They have a reputation to maintain, so even their lower line models shouldn't twist under braking. A laxed head tube angle provides more high speed stability. If the bike is designed for pedaling speeds, but it going ebike speeds, the added stability might be desired.

I used a Fox Talas for a while, which has adjustable travel (100mm-140mm) and now use a Fox Vanilla 160mm. The longer travel works great; no handling issues. The shortest travel made the bike more twitchy.

Yeah I like twitchy. Good to know. Yeah I had a feeling its just cheap. Why are downhill brakes more expensive then?
 
If you don't need long travel for your riding, but only improved stiffness, that's easy. You can either use a quality fork with short travel, or you can add spacers to a long travel fork to shorten its stroke.

I have a suspension fork with 25mm (steel) stanchions, but it's extremely stiff and controlled because I improved the crown and bracing arch, and because I shortened its travel to about 32mm (from the original 50ish).

redfront~2.JPG

Likewise, I have a 2004 Marzocchi Marathon 29er that was originally set up to give 80 or 60mm travel. I made it 60mm, beefed up the bushings and springs, and it's way more than adequately stiff, limited only by its 1-1/8" (but extremely thick-walled) aluminum steer tube.
 
MarkJohnston said:
Why are downhill brakes more expensive then?

Like everything else in a capitalist society that can be described as "expensive", it's because the market will bear it.

Some fools are more easily parted from their money than others. Downhill racers are surely fools, though.
 
MarkJohnston said:
The problem is that the fork is pulled to one side when using it,...
For me this problem was caused by loose front hub bearings. Wasn't actually the fork. Cleaned/repacked/carefully adjusted the bearings solved the wheel shifting under braking. So check that.

But for you:
MarkJohnston said:
...the stanchions are only 32 mm at their widest point. this fork is cheap and FLEXES like crazy,...
Yes, in your case there is that. What can you expect from a cheap front fork?

MarkJohnston said:
I ride like a mad man with tons of cargo.
So I have told you this many many times in previous posts (always some cheap piece of equipment failing), this will be my last reply to your "I ride like a mad man with tons of cargo" theme. So Don't Cheap Out. Don't Cheap Out. Don't Cheap Out. The stakes are too high.

Mad man + tons of cargo = Requires Good Gear.
 
I think I can pick up a bomber shock on pink bike for an affordable price. Yeah I know 99, I'm just always broke.


Also it hard to invest in a commuter bike with so many damn theives wondering around. I need a GPS and alarm system and an electric mesh to throw over the whole thing lol

Anyways I've pretty much narrows it down. Its not the wheel,(tested a bullet proof wheel) the hub, (freshly repacked) , or skewer (best shimano has to offer with old school cam) .its the damn fork.

Time to hit pink bike. I need to overhaul my headset anyways because a ton of water got in there and made it creaky will switch fork out at same timr
 
Chalo said:
MarkJohnston said:
Why are downhill brakes more expensive then?

Like everything else in a capitalist society that can be described as "expensive", it's because the market will bear it.

Some fools are more easily parted from their money than others. Downhill racers are surely fools, though.

This hope tech is loads better than the cheap shimano brake. I haven't even needed to bleed this yet. Its got a HUGE caliper too lol. Also really good modulation. My rear brake (mech KS Salmon's) locks up. Personally I likey brakes to lock up and do controlled skids but only on the rear. THE KS SALMONS HAVE TERRIBLE TERRIBLE PERFORMANCE IN THE WET. THE DISC WINS HERE BIG TIME
 
ilu said:
I have an older Rockshox Revelation fork with 32mm stanchions and when I changed it's travel from 120mm to 150mm it started to flex noticeably. Increasing the travel on that bike worked otherwise really well, especially as I could also make the wheelbase a bit longer with adjustable dropouts (Kona Honzo).

Newer Revelation on another bike has 35mm stanchions and it is clearly more stiff at 150mm travel. I would think that up to 100mm the 32mm diameter should be enough with a reputable brand forks but with longer travel I would get at least 35-36mm stanchions.

Huh. Someone told me otherwise. They said 32 mm wouldn't cut it . especially with a DH brake
 
Does anybody know where to pick up a brand new fork super cheap? I heard a lot of bike stuff is on super clearance right now
 
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