44mm head tubes- Fork selection

[kramnnim]

Trying to understand 44mm head tubes- one could either use a ZS/internal lower cup and a 1 1/8 straight fork, or an EC/external lower with a tapered 1.25" or 1.5" fork.

But the external cup will add...about 12mm of stack height, which will also affect the head and seat tube angles.

My frame came with a ZS lower and straight steerer-ed fork and I think it looks dumb, head tube is too fat for the skinny fork crown. I have a tapered fork that I could use instead if I swap out the lower cup, but am unsure about how much that ~12mm of stack height will affect how the bike actually rides.

[sales guy]

Trying to understand 44mm head tubes- one could either use a ZS/internal lower cup and a 1 1/8 straight fork, or an EC/external lower with a tapered 1.25" or 1.5" fork.

But the external cup will add...about 12mm of stack height, which will also affect the head and seat tube angles.

My frame came with a ZS lower and straight steerer-ed fork and I think it looks dumb, head tube is too fat for the skinny fork crown. I have a tapered fork that I could use instead if I swap out the lower cup, but am unsure about how much that ~12mm of stack height will affect how the bike actually rides.

The EC will only affect the HDT angle if the frame was designed with a ZS headset. Ours are designed with an EC head cup.

With a 44mm headtube you can do whatever you want fork wise- 1 1/8", 1 1/4" or 1 1/2" crown size. Up to you. Same with the headset. But again, if yours is designed for a ZS, stick with a ZS

[kramnnim]

It's an Alchemy...I've seen them with both ZS and EC. Guess I should ask them about it.

[sales guy]

Yeah. Cause the angles are based on the headset. If you have the drawing from bikecad check that. It would show it. But ask them. If they included a ZS headset, my guess is that's what they built it around and want you to use.

[sandyrs]

You could also switch to a shorter a-c fork in certain circumstances. If you’re using a 395 a-c cx fork, for example, then moving to an external lower cup and a 383 a-c “gravel” fork like the whisky 9 road+ will leave the geometry largely unchanged.

[tigoat]

If I do my quick math right, by adding 12mm of length to front end will change your head tube angle (and the seat tube angle too) by about 0.6 degree and lengthen the trail by about 4mm assuming the same fork spec. It will also raise your handlebar by some amount. This change in theory would make the front end more stable (slower response) but I don't believe it will have that much affect in practice. I have done it both ways by shortening and lengthening the front end by swapping forks and I did not find it to change that much on the road.

I personally like the look of ZS/Inset headset for both top and bottom. Having a ZS/Inset top and an EC/external headset at the bottom would look mismatch to me despite its popularity. Obviously, looks would be different with different people.

[NYCfixie]

Can someone help explain using an EC lower and ZS upper in a 44mm headtube.
I am finding both EC44 and EC49 for lower and ZS44 for upper.

This would be for using a tapered fork on a frame with a 44mm headtube built for an external cup lower.

Is the EC44 for a 1-1/8 to 1-1/4 fork and the EC49 for a 1-1/8 to 1-1/2 fork?

[NYCfixie]

Can someone help explain using an EC lower and ZS upper in a 44mm headtube.
I am finding both EC44 and EC49 for lower and ZS44 for upper.

This would be for using a tapered fork on a frame with a 44mm headtube built for an external cup lower.

Is the EC44 for a 1-1/8 to 1-1/4 fork and the EC49 for a 1-1/8 to 1-1/2 fork?


Think I figured out my own issue finally:

EC49/40 - tapered 1.5 headtube and 1.5 tapered fork
EC44/40 - 44mm headtube and 1.5 tapered fork
EC44/33 - 44mm headtube and 1.25 (aka 1-1/4) tapered fork

[d_douglas]

Can someone help explain using an EC lower and ZS upper in a 44mm headtube.
I am finding both EC44 and EC49 for lower and ZS44 for upper.

This would be for using a tapered fork on a frame with a 44mm headtube built for an external cup lower.

Is the EC44 for a 1-1/8 to 1-1/4 fork and the EC49 for a 1-1/8 to 1-1/2 fork?


I have wondered this myself.

1) My Desalvo was born with an ENVE QR disc 1 1/8" --> 1 1/4" fork

2) I switched it to a straight steerer Woundup and used the King devolution crown race.

3) I went TA and bought a Kona 1 1/8th --> 1 1/4" fork with an integrated crown race


Question: If I wanted to use a 1 1/8th to 1 1/2" tapered fork, would that work? Would I just need to get the bottom cup assembly and it'd work? All within a 44mm headtube?

I ask because it seems like 1 1/4" forks are becoming obsolete - if I wanted to buy a new (possibly flatmount) fork, I would have to go with a larger diameter?

[kramnnim]

Yes, if you have a 44mm HT you would just get an EC49 lower.

I have wondered this myself.

1) My Desalvo was born with an ENVE QR disc 1 1/8" --> 1 1/4" fork

2) I switched it to a straight steerer Woundup and used the King devolution crown race.

3) I went TA and bought a Kona 1 1/8th --> 1 1/4" fork with an integrated crown race


Question: If I wanted to use a 1 1/8th to 1 1/2" tapered fork, would that work? Would I just need to get the bottom cup assembly and it'd work? All within a 44mm headtube?

I ask because it seems like 1 1/4" forks are becoming obsolete - if I wanted to buy a new (possibly flatmount) fork, I would have to go with a larger diameter?

[NYCfixie]

I have wondered this myself.

1) My Desalvo was born with an ENVE QR disc 1 1/8" --> 1 1/4" fork

2) I switched it to a straight steerer Woundup and used the King devolution crown race.

3) I went TA and bought a Kona 1 1/8th --> 1 1/4" fork with an integrated crown race


Question: If I wanted to use a 1 1/8th to 1 1/2" tapered fork, would that work? Would I just need to get the bottom cup assembly and it'd work? All within a 44mm headtube?

I ask because it seems like 1 1/4" forks are becoming obsolete - if I wanted to buy a new (possibly flatmount) fork, I would have to go with a larger diameter?


1) EC, ZS, or integrated lower originally?

2) Cool.

3) Ok.


Answer: It depends. See #1. You cannot install an EC into a 44mm originally bored/reamed for a ZS (EC goes in further as far as I know) but I do think it can be bored/reamed deeper but then you are stuck with EC forever.

I do no think 1-1/4" are obsolete - there are still many options out there and they are better than 1.5 for smaller frames as smaller frames do not need the added stiffness.

Most importantly, you should contact DeSalvo for advice as there are other issues to consider: A to C, Rake, etc.

[zank]

Bottom cups
EC44/40 - external cup, 44 mm ID headtube, 40 mm OD crown seat (1.5")
EC44/33 - external cup, 44 mm ID headtube, 33 mm OD crown seat (1.25")
EC44/30 - external cup, 44 mm ID headtube, 30 mm OD crown seat (1.125")
EC49/40 - external cup, 49 mm ID headtube, 40 mm OD crown seat (1.5")
EC49/33 - external cup, 49 mm ID headtube, 33 mm OD crown seat (1.25")
ZS44/30 - internal cup, 44 mm ID headtube, 30 mm OD crown seat (1.125")

Most new aftermarket road disc forks are 1.25" (enve, parlee). A bunch are still 1.5" though.

The min bore depths is more dependent on head tube ID than headset style. In other words, generally the bore depth on a 49 mm ID head tube is deeper than a 44 mm ID headtube. It's not dependent on ZS vs EC.

[zank]

I have wondered this myself.

1) My Desalvo was born with an ENVE QR disc 1 1/8" --> 1 1/4" fork

2) I switched it to a straight steerer Woundup and used the King devolution crown race.

3) I went TA and bought a Kona 1 1/8th --> 1 1/4" fork with an integrated crown race


Question: If I wanted to use a 1 1/8th to 1 1/2" tapered fork, would that work? Would I just need to get the bottom cup assembly and it'd work? All within a 44mm headtube?

I ask because it seems like 1 1/4" forks are becoming obsolete - if I wanted to buy a new (possibly flatmount) fork, I would have to go with a larger diameter?

Is the integrated race a 45 degree race? If so, it will work with a cane creek EC44/33. Not with the King I8 though.

[NYCfixie]

Are most cross forks staying at 1.5?

Bottom cups
EC44/40 - external cup, 44 mm ID headtube, 40 mm OD crown seat (1.5")
EC44/33 - external cup, 44 mm ID headtube, 33 mm OD crown seat (1.25")
EC44/30 - external cup, 44 mm ID headtube, 30 mm OD crown seat (1.125")
EC49/40 - external cup, 49 mm ID headtube, 40 mm OD crown seat (1.5")
EC49/33 - external cup, 49 mm ID headtube, 33 mm OD crown seat (1.25")
ZS44/30 - internal cup, 44 mm ID headtube, 30 mm OD crown seat (1.125")

Most new aftermarket road disc forks are 1.25" (enve, parlee). A bunch are still 1.5" though.

The min bore depths is more dependent on head tube ID than headset style. In other words, generally the bore depth on a 49 mm ID head tube is deeper than a 44 mm ID headtube. It's not dependent on ZS vs EC.

[zank]

Pretty even split 1.5 vs 1.25.