Can a triple fork snap my head tube?

[Gavin67]

For my motorized bicycle I am using a 2007 hard tail huffy mountain bike. The forks were just regular steel forks no suspension on them. I have a dream of sorta making this thing a home made dirt bike just for casual trail rides. For now I was thinking about getting a triple fork (downhill fork, double crown fork) you know, but I hear if you put those on regular bike frames it can snap the head tube from all the stress.

This was from reading some other forum about a mountain biker wanting to put a downhill fork on his enduro trail bike. But when I searched for more, I couldn't really find anything. Is it really that bad to put a fork like that on a regular bike?

Can the BBR frames handle triple forks? Is this a ok frame to use for off-road or should I consider something else. And regarding off-road I have plastic guards on the frame to help prevent dirt from getting inside, I also sealed a gap between the choke lever so no dirt can get in there also.

 

[FurryOnTheInside]

How often or how hard do you like to crash?
I snapped my first mountain bike frame (steel GT Timberline) just using a 4.5" travel single crown fork. It originally had a rigid fork fitted. I'm sure I would have snapped it with any fork the way I rode that poor bike.

Actually one of the biggest problems is the change in geometry when you had a short ATC (axle to crown height) and you increase the ATC which raises your BB (bottom bracket) and slackens your head angle and seat tube angle. Makes the bike a real dog on anything but a near vertical downhill.

Long travel downhill forks are very active. About a third of the travel is just the sag (if they're set up correctly for the weight you put on them). We add weight with our engines and fuel.
Some types of fork can be adapted but you'll have to get reading into suspension tuning, and you'll still have a huge ATC. (Read ebike forums too!)

I wouldn't go further than an inch or two extra travel or extra ATC if you want to keep any of the nimble feel of the bike. So measure your ATC at present, then measure the fork you think you want and subtract 1/3 of the travel and that's it's ATC.

There are some lovely single crown forks out there and they are much cheaper for the same quality, or they're better quality for the same price, so unless you actually need a downhill fork they are better for you IMO.

 

[Timbone]

The better quality the fork, the safer you will be. Having a high strength fork should not stress the headtube significantly more. What you are probably hearing ppl voice is the experience of those riders who used good front forks on crappy frames. Think about it: if you suffer a failure, it will be in the weakest part of the system.

I think you would be better off with a good fork in a questionable frame rather than using a weak fork in a questionable frame.

 

[butre]

it can snap it, but that's just because they're stronger than a regular fork. any impact that could snap your steerer tube would have completely destroyed a normal fork.

 

[KB_UK]

The short answer is no it won't snap your frame.

The long answer is no it won't snap your frame, it will protect it, because the whole entire point of a suspension fork is to absorb shocks, stresses and strains that go into your front end. You're more likely to snap your frame with a normal fork.

 

[6blueoval9]

It's been my understanding the angle of the head tube has alot to do with being capable of safely using what is essentially a competition down hill type of fork...This why many advise against it on a trail bike with a more angled tube..Triple tree forks are basically heavy and anything below a certain angle places a bit more force on a head tube.

If you look at a "real" down hill bike you'll see the head tube angle is almost straight up and down in relation to the tubes which doesn't give as big of a chance of failure as a more laid back head tube.

 

[6blueoval9]

I would suggest maybe a good used mid to high end basic fork if you want something in the way of a front shock.

 

[6blueoval9]

I used to use SR Suntour Air forks...super light weight (under 5lbs) and priced under $300.. A typical cheap spring fork can weigh near 7lbs if not more...I'm afraid to see what those triple tree cheap forks weigh...probably nearing 10lbs.

 

[6blueoval9]

https://m.ebay.com/itm/Suntour-Epix...al-Lock/302399584746?var=&hash=item46686b79ea

 

[FurryOnTheInside]

I used to use SR Suntour Air forks...super light weight (under 5lbs) and priced under $300.. A typical cheap spring fork can weigh near 7lbs if not more...I'm afraid to see what those triple tree cheap forks weigh...probably nearing 10lbs.

If the weight is oil, lubricating and cooling the damping system, that's a good kind of weight.
I think it's better to have a good open oil bath system than something that saves weight by means of reduced oil volume. We don't have to pedal the thing uphill unassisted so I don't think weight saving is a big concern.
I would pay £45-£60 for single crown forks, Marzocchi Z1 BAM, Z3 QR20 around 17-19 years old. They are not too difficult to service. I got a first edition Z1 for my next build, though the BAM version is more practical.

I wouldn't want the disposable Suntour anything, personally.

If you need 6" travel then the upside down DNM USD 6 or aka DNM USD 150 are well reviewed, also O.O.B. system.
I had the Marzocchi Monster Triple, 8" travel fork with the 40mm stantions, it was a beast of a fork and unfortunately it got stolen but I think that weighed about 8kg but was soooo plush.

Ducati still spec Marzocchi O.O.B. system forks on their street bikes.