44mm head tube regrets. (A stiffness vs. harshness thread)

Discuss light weight issues concerning road bikes & parts.
morrisond
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Joined: Thu Mar 25, 2004 8:34 pm

by morrisond

Valbrona wrote:
morrisond wrote:
Wed Jan 10, 2018 4:19 am
I'm a big guy at at about 115kg.

I have an 853 Bike with ENVE 2.0 1-1/8 Fork. I had an Mosaic Ti 44mm HT with ENVE 1.25" Tapered.

Both are more than adequately stiff. Descending at 60+ km/h the 853 Front end is more than stiff enough, no performance issues.
??? You think that people are bothered about front-end stiffness when descending?
Your not? It's not very nice having a bike with lack of front end stiffness when you are leaned over and hit a bump mid-corner

by Weenie


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853guy
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by 853guy

bm0p700f wrote:
Wed Jan 10, 2018 1:39 am
stiff frames dont beat up riders, there are other reasons for that. The frame does not not absorb much road buzz the tyre does most of it. So if you are having a new frame made get it made with as big as possible clearance in mind. Brakes have a 49mm drop normally so select your frame and fork so you at the limits of that drop and can have the biggest possible tyre with your brakes.

That will make a much bigger improvement to ride comfort and going from a tapered headtube to a straight one. In reality the headtube make very little contribution to ride comfort.
pdlpsher1 wrote:I’m in the same camp that believes the frame stiffness has little to do with ride quality. Road vibrations create a vertical force. A bicycle frame is a triangular structure. The triangular structure is extremely stiff in the vertical axis, even with small diameter tubes. Big tubes in a frame will give you torsional stiffness, which is what you want for handling and efficient power transfer. Using smaller tubes will compromise torsional stiffness and it won’t help with the ride quality.

I’m a lightish rider at 60kg. I just took delivery of a Ti bike with a 44mm headtube and a T47 BB. It never entered my mind to use smaller tubes to improve the ride quality. To improve ride quality I got an Ergon suspension seatpost. Now I have the best of both worlds- a torsionally stiff bike with great handling and efficient power transfer, and a ride that is supremely comfortable.

Trying to soften the ride by using small tubes is not the appropriate approach.
Hello bm0p700f and pdlsher1,

I see what you’re saying. So let’s talk tire pressure first.

I come from MTBing. I’ve ridden and owned 26ers and 29ers, full-sus, hardtails and rigid bikes, running high-volume and low-volume tires, with tubes and without. And yes, tire pressure matters massively. In MTBing of course, you’re trying to achieve the greatest contact patch possible between the tire and the terrain whilst minimising rolling resistance. It’s always a balance, and the volume of air itself is dependent on the tire’s volume, its TPI, sidewall construction, whether its run front or rear and what you're riding over.

And yes, tire pressure massively impacts comfort.

But my experience of riding many different bikes of various types of steel, scandium, aluminium, titanium and carbon over varied terrain is that tire pressure in-and-of-itself is only one variable contributing to ride comfort. Even MTBs with large volume tires, fully suspended, and with attention paid to the right pressure can still ride harshly.

I say this not because I want to minimise the influence tire selection and pressure play (even on fully-suspended bikes), but because I believe bike comfort is a cumulative measurement, in which the frame, its geometry, tube profile, how those tubes are joined together combined with the cockpit, the saddle and post, all contribute to how we subjectively experience “harshness”, relative to the conditions we find ourselves in.

Many years ago I had a Bianchi SL3 Reparto Corse (my first foray into road). Didn’t matter what tires, of what volume, at what pressure (or on what wheelset, although that helped)… that thing rode like a cheap piece of patio furniture. It wasn’t just expansion joints and potholes either, it was after the ride where I’d come home feeling exhausted in a way that had nothing to do with my fitness. It was just a tiring bike to ride. Again, it’s a subjective thing, but mirrored my experiences on MTBs of lesser compliance relative to their frames and the way they were constructed.

So while I completely concur attention needs to be paid to tire selection and pressure, it’s only one of many variables, and those variables all add up. Everything matters, to greater and lesser degrees. But given this will be a custom build, it seems pertinent at this stage of the process to think through the degree of stiffness relative to harshness a 44mm head tube may confer, even if its contribution to stiffness/harshness is small comparatively speaking.

As to tire volume, I do plan to ask for relatively generous clearance, and to run ee brakes. However, I also plan to run Lightweight Gipfelsturm/Obermayers (maybe as a combo), so tire volume will likely be more limited than were I to go for a wheelset with larger internal rim width.

I guess stiffness relative to harshness is going to be a personal and very subjective thing. It’s part of the reason I’ll work with a builder who'll hopefully have insight into the line in which the particular tubeset, tube diameter and geometry we choose for my bike cross that line, or veer near it. I could of course go for a stiffer 44mm headtube and pair it with a flexier fork, or go for slightly heavier wheels allowing larger volume tires - these are the kinda compromises/tradeoffs one must make after all - but until I start conversations with the builder I can't definitively say how much the headtube in-and-of-itself will contribute to the overall feeling of the bike.

Nevertheless, at this stage, and thanks to all y’all feedback, it would seem a 44mm head tube seems unnecessary for my size, weight and riding preferences, and the weight saving that’ll come from a slightly lighter front end won’t be lost on the WW in me.

Cheers!

853guy

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853guy
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by 853guy

pdlpsher1 wrote:
Wed Jan 10, 2018 2:52 am
Don’t get an Enve fork. For my custom Ti build I went with a Trek Domane full-carbon tapered fork. It uses Shimano’s direct mount brakes. It has loads of tire clearance. I put in a tire that measured 31mm wide. There’s still a 3mm clearance between the tire and the fork on each side. For $300 delivered to my local Trek dealer it’s hard to beat! The uncut fork weighed 350g. After cutting it weighed 300g. It comes in three different rakes, and several colors to choose from. The fork also has an integrated carbon crown race. So you save the weight of the metal crown race which in Chris King’s case it was a lot of weight saved.
morrisond wrote:I'm a big guy at at about 115kg.

I have an 853 Bike with ENVE 2.0 1-1/8 Fork. I had an Mosaic Ti 44mm HT with ENVE 1.25" Tapered.

Both are more than adequately stiff. Descending at 60+ km/h the 853 Front end is more than stiff enough, no performance issues.

You can save probably 100+ grams by going with the 1-1/8 HT vs a 44mm HT - they are really heavy.

If you want the best 1-1/8" Fork you should try and get a THM Scapula - 50-60 grams lighter than ENVE and rides a lot better than ENVE (as measured by TOUR - it deflects more fore to aft) but it's stiffer in the corners as well.

They don't make them anymore but I know a shop where you can find a brand new one. PM me if you are interested.
Hi pdlpsher1 and morrisond,

I’m certainly open to suggestions on other fork choices.

Have to admit the THM had been pencilled, but the cost/weight saving ratio over the ENVE is not overly convincing, given those “savings” could be allocated to other things for increased weight saving (say, cranks). I hadn’t considered the Trek. Aesthetically, it’s not really my cup of tea, and if I go with IF it’s likely they’ll have more experience with designing the frame around the ENVE.

Initially at least, I’ll probably look to work with the builder’s choice of fork, so that the stiffness/harshness equation can be worked into the design of the frame, and then potentially experiment with other forks should I find anything wanting.

Again, really appreciate your thoughts and perspective.

Cheers!

853guy

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853guy
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by 853guy

boots2000 wrote:
Wed Jan 10, 2018 12:47 am
I had a ti bike with a 44mm headtube that I thought was too stiff.
But it had a 1.5 top tube, a 1.75 downtube, and a tapered 1.5 fork.

Can you get a fork that is 11/8-11/4 tapered? I think that and not going crazy OS in terms of tubes will ride nicely.
Hi boots2000,

Cool, interesting data point.

A tapered fork is a possibility, but I’m going to lean on the builder’s gut instinct as to whether in my case it’ll confer any benefit over a 1⅛ steerer. As I mention above, tubeset is likely to be XCr.

Frame design and building is an asymmetrical venture. The tiny details of tube selection, geometry and build all have far-reaching and significant consequences. So this will be a process in which I bow to the greater wisdom of the builder and trust that their experience will dwarf my enthusiasm, and provide significant gains relative to losses in the areas that matter to me. Hopefully, by the time we begin said process, the feedback that I’ve gained from this forum will be sufficient to allow me to articulate exactly what I (think I) want, and perhaps as importantly, what I don’t.

Best,

853guy

pdlpsher1
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Location: CO

by pdlpsher1

Here's a good guide on the various headtubes types custom builders use. I have the 44mm straight HT and it gives the greatest compatibility with headsets and forks. I have the Chris King Inset 7 headset.

http://paragonmachineworks.com/files/pu ... eGuide.pdf

When I looked at the various HTs that Paragon offers, I don't see any 34mm HTs being listed. I get the impression that 34mm HTs are no longer being used by frame builders. Click on a common HT length like 140mm and see for yourself.

http://www.paragonmachineworks.com/fram ... tubes.html

pdlpsher1
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by pdlpsher1

For tuning a frame for ride characteristics, the head tube is the one that has the least effect on the ride. Your builder should pay attention to the chainstay length, the seat tube and head tube angles, and the fork rake. I'd use a 42.5mm chainstay length, a shallower seat tube angle such as 72.5, a shallower headtube angle of 72, and in combination with a fork rake of 48mm or greater. This combination will give a stable handling and a smooth ride.

morrisond
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Joined: Thu Mar 25, 2004 8:34 pm

by morrisond

Columbus makes XCR HT's for both 44mm and 1-1/8 Forks

http://www.columbustubi.com/pdf/Columbu ... gue-V3.pdf

nickf
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Joined: Sat Mar 06, 2010 10:34 pm

by nickf

pdlpsher1 wrote:
Wed Jan 10, 2018 8:24 pm
For tuning a frame for ride characteristics, the head tube is the one that has the least effect on the ride. Your builder should pay attention to the chainstay length, the seat tube and head tube angles, and the fork rake. I'd use a 42.5mm chainstay length, a shallower seat tube angle such as 72.5, a shallower headtube angle of 72, and in combination with a fork rake of 48mm or greater. This combination will give a stable handling and a smooth ride.
This^
Just got my English with a 1 1/8 straight steerer. Nothing about the front end is "soft" Used a 50mm Enve 1.0 fork. Bike handling is super responsive with no noticeable flex in the front end. The only flex i can maybe feel on the fornt end is the MCFK stem I'm using. I want my stiffness out back when i'm putting power to the rear wheel, and that's that Rob builds. Small tight rear triangle that's super snappy.

Now if your going for aesthetics bigger tubes with the 44mm HT looks good. But many of these modern steel bikes with a straight 44mm HT and a Columbus life 28.6 TT stuck to it just looks bad. At least use a tapered HT. King Cielo for example (maybe a 31.7 TT) still, bleh.

shimmeD
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by shimmeD

The blue V3? Nice one! That's a front end very nicely done. Rob knows how to design, and build bikes.
Less is more.

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853guy
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by 853guy

pdlpsher1 wrote:
Wed Jan 10, 2018 8:24 pm
For tuning a frame for ride characteristics, the head tube is the one that has the least effect on the ride. Your builder should pay attention to the chainstay length, the seat tube and head tube angles, and the fork rake. I'd use a 42.5mm chainstay length, a shallower seat tube angle such as 72.5, a shallower headtube angle of 72, and in combination with a fork rake of 48mm or greater. This combination will give a stable handling and a smooth ride.
nickf wrote:This^
Just got my English with a 1 1/8 straight steerer. Nothing about the front end is "soft" Used a 50mm Enve 1.0 fork. Bike handling is super responsive with no noticeable flex in the front end. The only flex i can maybe feel on the fornt end is the MCFK stem I'm using. I want my stiffness out back when i'm putting power to the rear wheel, and that's that Rob builds. Small tight rear triangle that's super snappy.

Now if your going for aesthetics bigger tubes with the 44mm HT looks good. But many of these modern steel bikes with a straight 44mm HT and a Columbus life 28.6 TT stuck to it just looks bad. At least use a tapered HT. King Cielo for example (maybe a 31.7 TT) still, bleh.
Hi pdlpsher1 and nickf,

As I mentioned in my original post, “Given my size and weight, I’m not sure any of the benefits of the larger head tube will be realised in my case, and that a traditional 1 ⅛” steerer won’t in fact be more than adequate (for a planned XCr frame with an ENVE fork).”

The only reason I’ve enquired about the 44mm option is because Indy Fab offers it. Again, everything matters, and although I appreciate the fact the head tube is only one variable of many that contributes to stiffness and ride quality, it seemed pertinent to canvas the opinions of those who’ve experimented with the larger diameter and whether they had experienced any regret later.

Totally agree, pdlpsher1 - Indy Fab have built plenty of bikes, so I feel fairly confident they’ll sweat the details of chain stay length, seat and head tube angle on my behalf (as I’m sure will the other two builders I have shortlisted). Interestingly, Indy Fab’s “traditional” geometry is pretty close to your ideals above: for a 52cm frame, head tube angle is listed as 72, seat tube angle is 73 degrees, fork offset of 50mm and 425mm chain stays. Hard to argue with that.

And nickf, I totally agree about the slightly weird aesthetics of matching a 44mm head tube to traditional diameter top tube. I plan to have this bike for a long, long time, so keeping things somewhat classically inspired (including the paint job) seems wise.

Cheers to you both,

853guy

GothicCastle
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by GothicCastle

I’ve ridden a Titanium Guru (RIP) that I’d definitely characterize as borderline overly stiff. It was a compact road model with oversized tubes. I don’t remeber anything about the headtube, but it was definitely not tapered.

I have a Waith Fabrication Hustle (Columbus Spirit) with a tapered headtube and the front end is quite stiff. Between that front end and the aluminum Zipp bar and stem I have on it, I really do have to pay attention on bad roads. Bumps can easily bounce the bars out of my hands if I don’t have a good grip. It is a marked difference from my Parlee, which has a much smoother ride. Interestingly, I had a Pro bar and stem on that bike that was too noodly, so I swapped them out.

This isn’t to say that I don’t like riding the Hustle; I did something like 4000 miles on it last year. It is just part of the bike’s character.

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