daven1986

Hi,

I have a road bike (giant scr1) https://www.giant-bicycles.com/_uploa...R%201%2008.jpg and I want to replace the fork so I can use disk brakes.

As you can see from the picture the frame has an internal headset, is it possible to use any replacement fork or would it have to be a specific one to fit?

Thanks

Daven

dabac

It looks like that is a regular 1 1/8 steerer tube, so there'd be plenty of forks that'd mount up to the frame at least. Your issue will be that disc-brake ready road-specific, or even CX forks aren't that common yet. Finding one with a decently matching axle-to-crown and rake might be a challenge. I'd measure the ATC, then probably look for a supposedly 26", sus corrected disc brake fork to use as a replacement. Failing that, maybe a hybrid disc brake fork.

daven1986

awesome, that is good news thanks. I have found a few forks in my travels, but I'll make some measurements and begin searching!

thanks again

daven

jimc101

All you need is a 700c disc fork, plenty of these are now becoming available, would not want to even think about running a 26" suspension corrected fork on this, as you will have geometry issues, and fit issues with the wheel. You want to be looking at something like this https://shop.upgradebikes.co.uk/Catal...s/Kinesis-DC37

You will also need a new wheel, and road specific calipers, also, you will need to make sure that the calipers are compatible with your STI's, for the stock shifters on this bike, either Shimano R505 or AVID BB5/7 road

daven1986

Yeah I was thinking of getting a 700C carbon disc fork, with BB7 calipers, and then I'd build up a wheel with a dynohub I have

Guess I'll just need to find a compatible crown race

jimc101

Your crown race is specific to your headset, either get your current one pulled, find the manufacture of the headset and get a replacement, or get a new integrated lower which will come with one.

dabac

And what would those be?

jimc101

You said 'then probably look for a supposedly 26", sus corrected disc brake fork to use as a replacement.'

The OP has a 700c road bike, there may be clearance issues with the wheel/tire and fork crown, this would need to be looked at on a fork by fork basis, if the OP was to get a 700c fork, this wouldn't need to even be considered.

Add to that, most rigid carbon MTB forks are just round tubes, this would look pretty bad on a road bike.

HillRider

I assume the smiley means the dynohub comment was a joke. If not, does the hub have disc mounts?

dabac

Highly unlikely.
26" MTB forks are generally roomy enough to take a 700C wheel with a skinny road tire even if they aren't sus corrected. Mud and fender clearance tends to see to that.
If you use a sus corrected one you're probably looking at a tad of ATC increase compared to the original fork.

Well, in terms of the wheel not fitting, it doesn't have to be considered either.
But sure, a 700C disc fork may be an overall better replacement in terms of rake and ATC. Either way, my impression is that there are more sus corrected 26" forks available than there are 700C disc brake road forks

... if the OP insists on having a CF fork. There's a Mosso aluminium fork and an 413 mm ATC with rather nicely tapered fork legs for instance

jimc101

That's why I italic'd the may, you are probably correct 99% of the time, what if the OP is that 1%?



Got to go with, so what if there are less 700c forks; the fact is, that they are available, and more are coming every year.


There are very few non carbon disc forks left on the market, the Mosso you suggested isn't widely available in the UK (the OP has their country listed as UK, so relevant), carbon forks are. The Mosso forks are available on Ebay from HK seller, fairly cheap, but there is no warranty for the buyer, and they could get hit with VAT/import duty before the item is released from the courier, which isn't an issue in some non-EU countries.

anixi

This looks like it fits the bill:

https://www.ebay.com/itm/700c-Used-Cr...item53f2beb2a0

ships worldwide.

or, for cantis/v-brakes:

https://www.ebay.com/itm/700C-CRO-MOL...item5884e31609

dabac

You seem to be missing a piece here. Most standard 26" MTB forks will take a 700C wheel with a narrow tire AKA a road bike wheel straight off. Here, there may be trouble.

But if you use a sus-corrected 26" MTB fork you'll end up with more ATC and clearance than a regular road bike fork.

Anything short of a 700C balloon tire should fit right in, and then we're outside the "road bike" definition, vague as it is.

All I'm saying is that IMO it's probably easier (and cheaper) to track down a supposedly 26" fork that'll do the job.
If the OP prefers to invest more time and money to source a 700C fork, that's his decision.
Or maybe I'm wrong and 700C disc forks are easier to find.
Get the ATC (and rake) right, and the 700C or 26" designations won't matter. The wheel will fit and the bike won't care. If quality is assumed to be equal, either fork will do.

The OP was thinking about CF, not insisting on it.

If I could get one, so can the OP. I'm under the impression that most people are quite pleased with Ebay.

Granted, you've got a couple of points there.

phidauex

You guys are making this too complicated - there are a variety of 700c disc forks available in carbon, at a range of prices. Most of them are intended for cross bikes, which means they will have a slightly longer axle to crown length. I can't tell what the axle-to-crown measurement is on the stock SCR 1 fork, but it is probably 370-375mm or so. Most cross 700c forks will be in the 395mm range. Cross forks will tend to have a very similar rake, ~45mm.

This will have the effect of raising the front of the bike by 3/4" or so, which will slacken the headtube and seat angle. This will require a slight fit adjustment, and will change the bike handling slightly, but whether it is an improvement or not is a matter of opinion - certainly many people like a slightly more slack angle, especially if they are planning on longer rides or commuting (as a dynohub suggests).

My recommendation, once you are sure that your steerer is a 1 1/8" steerer (rather than the possibility of a 1 1/8" to 1 1/2" tapered steerer, though the pictures make that seem unlikely), would be this Carver: https://www.carverbikes.com/comp/carbon-cx-disc-fork It is well built, carbon steerer, and reasonable price. Make sure you buy a compression plug for another $20 - you can't use star nuts with carbon steerers. You can go fancier if you want, Enve and Whisky have good options as well, though you are getting into the $400+ range.

-Sam

daven1986

Thanks for all the advice guys, it has been very helpful. In terms of the headset I've been having trouble finding out which one it is. If I wanted to replace it, what should I be checking to ensure compatibility?

Thanks

Daven

phidauex

Well, there are a few ways to determine if you have a tapered headset or a straight headset. The first is just visual - if your headset is tapered, the head-tube will usually be tapered as well, starting out a smaller diameter, and getting wider as it goes down. You could also just partially disassemble the headset and fork to see for yourself. A tapered steerer fork will start at 1 1/8" and then taper out to 1 1/2" at the crown race (at the top of the fork itself). A straight steerer will be 1-1/8" the whole way. These instructions from Park Tool are overly complex (they go through an entire replacement procedure), but should give you a good idea of what is in there, and how to disassemble and reassemble correctly. If you buy a new fork, you'll need to pull off and move the crown race from the old fork to the new fork, cut the steerer to the correct length, and then reassemble - a headset replacement won't be necessary. Forks with carbon steerers also need an "expansion plug" instead of the "star fangled nut" you see in most instructions.

https://www.parktool.com/blog/repair-...eadset-service

-Sam

daven1986

Ok thanks, I guess I can just reuse the old crow race then. However if I were to require a headset replacement in the future - would any old headset that is 1 1/8" or 1 1/2" compatible do?

jimc101

Are you sure you have a tapered headset, they were uncommon back in 2008, and the bike you have linked to in the first post looks to just have an integrated headset, can't see the tell tail bulge at the bottom race.

If you have an integrated headset, you could just buy replacement bearings, a good LBS should have these in stock, you would probably find it easiest to take the bike in, so they can ID what you have, and so you get the correct ones.

phidauex

Yeah, jim is right - it is unlikely to be tapered if it is from 2008. The headset may well be integrated though.

Honestly I wouldn't worry about buying a new headset unless your bearings are worn - are you feeling grinding or stiff spots in the headset when you rotate the fork? If not, then I'd just leave them be.

daven1986

Cool thanks guys, looks like I now have a project