Just want to make sure I have this right.

Cannondales (Rush inparticular) have 1.5 inch headtubes. So if I want to use 1 1/8 forks I can either:

– Use a set of Cannondale Reducer Cups and a normal headset.
– Use a fsa/cane creek/hope etc 1.5 step down headset

But i’ve heard that not all step down headsets work due to insertion depth and others which are internal step down headsets which are internal (0mm stack hieght) can cause the fork to catch on the frame.

Question to singletrack:

– Are these assumptions correct?

– Can people recommend headsets which will work and which wont.

– Does anybody have some cannondale reducer cups knocking around that they may sell me in exchange for beer money or regular money? 🙂

On my prophet I used a hope 1.5″ – 1 1/8″ reducer headset, after removing the cannondale reducers of course.
The hope reducer headset comes in 2 types. I got the one with an extra bit (10mm i think)extending off the bottom cup (eg not flush fit) to prevent the forks (pikes for me) hitting the downtube.
The pikes do clear, but I suppose it depends on your actual fork/frame combo as to whether they would clear.

It saved a fair bit of weight (the cannondale reducer cups are pretty beefy) and lowered the stack height no end (i wanted my bars a bit lower).

Hope that helps.

Hi, I’ve used one of these to successfully fit a 1 1/8″ fork to a ‘Dale with no problems. Similar headsets should work fine. This one may cause the fork catching issue (it din’t with the fork I used), so you might want a ‘normal’ type one.

http://www.windwave.co.uk/windwave/101-1312.html

This one might be better if you have issues with the fork hitting the downtube:

http://www.windwave.co.uk/windwave/101-1250.html

I think it’s a neater solution than using the reducer cups really.

These aren’t Cannondale specific, because the ‘Dale headtube is something like 1.56″ wide, but they will work, and I’ve seen FSA headsets as OEM on ‘Dales with fat headtubes and standard forks.

Reducer cups should be about £25-30 a set though I’d imagine.

Yep £25 for reduced cups – I’ve used them on a couple of Cannondales to put 1 1/8 forks on them with a CK headset.

Didn’t realise the headtube is not exactly 1.5 inch.

It’s a tiny bit bigger, but just a really, really tiny bit. Makes no difference in the real world. I fitted a reducer headset and it was fine.

Reducer cups weren’t great for me as there was a tiny amount of play. Used a Hope step down on my F500 hard tail. Get the one with 10mm lower stack height if you are worried about zero stack issues.

No hang on I’m just confuddling myself…

The steerer diameter on ‘Dales is 1.5″, not the headtube diameter.

Which is why the reducer headsets work fine, as the headtube diameter is the same. Apparently. Well, it’s worked for me perfectly is all I can say.

IE; a Cannondale steerer (Headshock, Lefty) won’t go through a 1.5″ headset. ‘Dales with 1.5″ forks use a 1.5″ headset.

An FSA, Hope, CaneCreek etc reducer headset will work fine. On Cannondale headtubes, there is a maximum insertion depth, so some reducer headset cups go in too deep. I believe this is only on older frames though.

Rik – the headtube is 1.5″.

Lefty/headshock steerers are 1.56″, so you need the special c’dale cups/bearings for those.

For other forks, you just need a normal 1.5″ or 1.5-1+1/8″ step down headsets, depending on your steerer size.

As for insertion depth – I only thought this was a problem on older frames, but I guess you might still have problems with some internal cup / zero stack types?

Anyway, a 1.5″ to 1 1/8″ step down Superstar headset works fine for me (which is zero stack incidentally).

Okay cool I’ll have to have a look at the frame and the insertion depth to see if there’s a rim or ridge to stop it going in.

I’m pretty sure it’s not bigger. I put a standard external cup 1.5″-1 1/8th” headset in my Prophet. The forks clear the down tube and all is right with the world.

Rik – the headtube is 1.5″.

It’s not. The headtube internal diameter is just a smidge under 2″. I know this, as I actually have a reducer cup in front of me as I type, and I’ve just measured it…

Rik; I have 2 lots of reducer cups, but I can’t find the upper cups, only have 2 lower ones (used 2 upper cups as the stack height is minimal and I had a short steerer to contend with). Dunno where I’ve put them. If I can find the upper cups, I’ll give you a shout, but tbh, I think a reducer headset is the best option really.

A bit of Googling revealed another thread on this very same issue! My own post here explains things:

http://www.singletrackworld.com/forum/topic/doh-removed-headshok-and-tried-to-fit-new-1-15th-fork#post-1757881

Elfinsafety – Member
Rik – the headtube is 1.5″.
It’s not. The headtube internal diameter is just a smidge under 2″. I know this, as I actually have a reducer cup in front of me as I type, and I’ve just measured it…

*rolls eyes*
I mean (obviously) that it is the same size as any other headtube designed for 1.5″ headsets.

Oh right ok. 😀

It’s a right confuddling issue though. Even I have to stop and think about it, and I’ve done the conversion!

Cannondale/OnePointFive standard internal headtube diameter = 49.61mm.

There. All sorted. 🙂

Elfin – if you can find them that would be great. I already have a nice 1 1/8 headset and I don’t mind the extra stack as it will slacken if off slightly.

Elfin – even better if you can find the upper cups too

Well I’ve had a scout round and can’t find them, but I think they may actually be at a friend’s house, and I know she had a clearout a while ago, so I fear they may be lost forever. 🙁 I’ll give her a call over t’weekend, but she’ll probbly say she’s chucked everything out, tbh. They won’t have meant owt to her, so she’ll not have thought them important. 🙁

Stick up a wanted on classified? Have a scout on Ebay?

I definitely think the reducer headset is the best option, because it’s just one set of cups pressed into the frame rather than two, and less chance for creakage. The reducer cup option was a compromise before OnePointFive headsets (and subsequently reducer headsets) became common.

And getting the headset cups out of the reducer cups is a right faff, let me tell you.

I have a Cannondale reducer headset that I ahve just pulled from my Prophet frame. It has a low stack upper cup and a high 20mm lower cup.

If you’re concerned and want to usethe genuine Cannondale component, give me a shout, jjmcewan AT btinternet DOT COM, and perhaps we can do a deal.

Cheers, Joe.