# Converting to rigid fork.



## Milkfloat (6 Apr 2017)

I need some help. I want to convert my 1997 front suspension Trek 970 to a rigid fork. I use it as a commuter and occasional tourer. Obviously I want to do this on the cheap, as despite it being much loved, it is not exactly worth spending a huge amount on.

It is the same as this:







Now the big question, what would be the effect of not having a suspension correct fork? Is it really that important? I assume the front end will just be a inch lower, or is there more to consider?

I was looking at getting one of these http://www.ebay.co.uk/itm/391580837203


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## Crackle (6 Apr 2017)

Ideally axle to crown length should be the same or a bit less on the rigid once you allow for fork sag. Is your headset 11/8th, a lot of them were 1" on earlier bikes, so check that.

If you don't get it exactly the same height then every 20mm height difference will equate to about 1 degree difference in the head angle. It would have to be quite different I would suggest for you to be able to tell. There are other things like fork rake but that shouldn't be radically different.


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## smiler1207 (6 Apr 2017)

I would like to convert my Carrera Crossfire too, I know you can get suspension adjusted solid forks but they are £££


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## Milkfloat (6 Apr 2017)

Crackle said:


> Ideally axle to crown length should be the same or a bit less on the rigid once you allow for fork sag. Is your headset 11/8th, a lot of them were 1" on earlier bikes, so check that.
> 
> If you don't get it exactly the same height then every 20mm height difference will equate to about 1 degree difference in the head angle. It would have to be quite different I would suggest for you to be able to tell. There are other things like fork rake but that shouldn't be radically different.



Unfortunately all the sellers are not able/willing to give me the A-C measurement. Even trying to find out if it is 1 1/8th and threaded or unthreaded is tricky.

The fork I linked to looks threaded in the bad picture, but the text says 1 1/8th Ahead without thread.


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## Crackle (6 Apr 2017)

Milkfloat said:


> Unfortunately all the sellers are not able/willing to give me the A-C measurement. Even trying to find out if it is 1 1/8th and threaded or unthreaded is tricky.
> 
> The fork I linked to looks threaded in the bad picture, but the text says 1 1/8th Ahead without thread.



I presume something like this is just too much

http://www.on-one.co.uk/i/q/FOOOCR26DV/on-one-cromo-26er-mtb-fork-v-brake--disc


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## Milkfloat (6 Apr 2017)

Crackle said:


> I presume something like this is just too much
> 
> http://www.on-one.co.uk/i/q/FOOOCR26DV/on-one-cromo-26er-mtb-fork-v-brake--disc



yeah - I would like to keep it cheap. if i was going to spend more I would go carbon http://www.ebay.co.uk/itm/CARBON-bi...or-26er-27-5er-29er-gloss-matte-/122140439953


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## clockworksimon (6 Apr 2017)

May be cheaper to get a cheap second hand rigid fork MTB and scavenge the forks. Something like an old Hardrock. Obviously need to check if it's an aheadset, the headset size and it's not a smaller frame/shorter head tube. 

Might even work out better to sell yours and get a second hand 90's rigid bike. You could end up evens money wise.


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## Milkfloat (6 Apr 2017)

clockworksimon said:


> May be cheaper to get a cheap second hand rigid fork MTB and scavenge the forks. Something like an old Hardrock. Obviously need to check if it's an aheadset, the headset size and it's not a smaller frame/shorter head tube.
> 
> Might even work out better to sell yours and get a second hand 90's rigid bike. You could end up evens money wise.



That could be an idea. I won't be selling mine, we have been through too much together, but finding a suitable donor is sounds worthwhile.


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## ChrisEyles (7 Apr 2017)

I did this on a '97 Marin Hawk Hill a while ago. The RST bouncy forks were quite long, around 455mm axle to crown. Like you I didn't want to spend a lot on a new pair of rigid forks, and all the cheap ones seemed to be 395mm axle-crown, which is a big difference! Fork rake seems to be much more consistant, around 50mm for everything. 

I ended up getting a fork off of retrobike from a similar age Marin. It was a bit shorter at 425mm axle-crown, and I did worry this would upset the handling, but I honestly couldn't tell the difference when I made the swap (well obviously rock gardens were a bit more interesting without the bouncy fork!). 

In theory a shorter fork will make the handling sharper/twitchier. If that doesn't sound like a bad thing, and you don't worry much about going over the bars on any of the routes you intend to use the bike for, I'd give the cheap forks a go and see how you get on. 

I'm really pleased with my rigid conversion, it's great fun to ride. Looks like your Trek would make a cracking rigid bike too.


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## clockworksimon (7 Apr 2017)

Milkfloat said:


> That could be an idea. I won't be selling mine, we have been through too much together, but finding a suitable donor is sounds worthwhile.


Know what you mean about the old bike. Broke a rear dropout last year on my 1994 Orange and went through the dilemma of whether it was worth fixing. Looked at lots of cheap second hand bikes which were fine but got the frame repaired in the end. Me and the bike have lots of history together. Glad I did this.

If you really like the old bike and will use it a lot maybe it's worth paying for decent new rigid forks rather than messing about?


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## Milkfloat (7 Apr 2017)

Well I ordered the cheap fork that I linked above. Worse case I will lob it in the spares box or sell it on. My A-C measurement is almost 500mm, so certainly it is going to be lower. I don't go properly off-road on it, so hopefully I won't kill myself.


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## Crackle (7 Apr 2017)

Milkfloat said:


> Well I ordered the cheap fork that I linked above. Worse case I will lob it in the spares box or sell it on. My A-C measurement is almost 500mm, so certainly it is going to be lower. I don't go properly off-road on it, so hopefully I won't kill myself.


Or use it for wheel truing.


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## Drago (7 Apr 2017)

Plenty on On One branded rigid forks on Planet X, many of which are suspension corrected.


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## Milkfloat (7 Apr 2017)

Drago said:


> Plenty on On One branded rigid forks on Planet X, many of which are suspension corrected.



Crackle suggested guess worse case I will wait for a 50% sale.


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## ChrisEyles (8 Apr 2017)

If the fork is loads shorter than the current sus fork, you might end up with a slight downward slope to the top tube of the frame - which looks bad-ass! 

The only thing I'd watch would be steep descents off-road, as the over-the-bars risk will be a bit higher.


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## Salar (11 Apr 2017)

Drago said:


> Plenty on On One branded rigid forks on Planet X, many of which are suspension corrected.



I did my Kona with On Ones, straightforward job and sold the suspension forks to cover the costs.







One day I'll put the mudguards on!


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## Milkfloat (17 Apr 2017)

Fork arrived and I have semi fitted it. There is a difference of 95mm in the axle to crown measurement which it quite a lot. It does not seem too twitchy though, which could be down to my long stem. I am going to try a huge stack of spacers to get the bars higher, but am worried that the already too short top tube is going to end up even shorter.


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## Milkfloat (19 Apr 2017)

A huge stack of spacers later and I am left with this. A monstrosity, but I think functional. Now I need to fine tune the height, top off the steerer tube and refit the front mudguard.


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## ChrisEyles (19 Apr 2017)

Wow - that would be pretty racy looking with the stem slammed!! I like it, looks like a solid workhorse do-it-all sort of bike 

Might be worth checking with someone who knows their stuff (I don't) if it's structurally sound having that many spacers under the bars from a leverage point of view, but I guess if you're not doing crazy off-road stuff on it it's not a biggie. 

I'm curious though - can you feel much difference in the handling after the swap?


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## Drago (19 Apr 2017)

That's a lot of exposed seat post. How much is still in the frame?


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## Crackle (19 Apr 2017)

It looks OK. If it feels OK, job's a good un. Don't forget, suspension sag on the old forks will make the difference less than 95mm. That amount od spacers is nothing in comparison to Thorn Sherpas.


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## Tangoup51 (19 Apr 2017)

_Hell'a flush, yo. _


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## Milkfloat (19 Apr 2017)

Drago said:


> That's a lot of exposed seat post. How much is still in the frame?



It is a 600mm seatpost, so plenty left. It is my first proper MTB before I stopped growing, so I have always done my best to keep it going. The Trek is one of the last steel frames still made in the USA, most of the components are original and the ones I have had to swap out are safely stored in case I want to go back to its original setup.


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## Milkfloat (19 Apr 2017)

ChrisEyles said:


> I'm curious though - can you feel much difference in the handling after the swap?



It is really not too bad. I think the long stem helps. I will mess around with the spacers until I have got a good balance between all day comfort and efficiency.


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