Longest top tube 50 cm frame?
 

TL;DR - shortest height frame with 57 cm TT, or longest 50 cm c-t frame? Aero frame but can be used in mass start.

TL;DR Part 2 - if no real aero benefits to frames I'm considering then would it make sense simply to commission an aero "style" frame? Not sure of USI legality due to fact that builder is not UCI legal. It would use regular tubes plus a commercially available fork.

I've been reading a lot of back posts on track racing. I'm looking to get into it a bit more, starting with getting decent equipment (right now I'm riding a straight gauge steel frame/fork that weighs just over 7 lbs for frame/fork/headset alone).

My target event would be the 500m, then in order of enjoyment, keirin, scratch, sprint, and whatever else. I'd probably get aero bars as well as drop bars because based on my power profile I think I'll need to get aero bars to be competitive in the 500m. I have zero interest (and capability?) in doing longer timed events.

Realistically I would not be racing much, and in fact I'm looking at this as a real splurge because the closest tracks are so far away. If it ends up becoming a thing then I'd commission a second frame (aluminum) to mirror the position of the primary "aero carbon" frame.

My road bikes are sloping top tube frames but effectively:
ST - 50 cm c-c
TT - 56.5 TT
HT - 12 cm (9.5cm + 21.5mm headset)
STA - 75.5
(HTA - 73 deg)

Stem - 14.5 cm / -32 deg (would be -33 if using 74 deg HTA frame)
Bar - (FSA Compact) 12 cm reach, 8 cm drop

I'd like the head tube to be 12 cm or so, TT seems like it should be 57 or even longer?, STA close to 75 deg.

I run an ISM saddle so I should be okay with saddle fore-aft legality, on the BB vertical line for sprints, 4 or 5 cm back for time trial set ups.

So far the only frame that seems to fit those dimensions is the Dolan DF4 which looks like the HT length stays the same through the 57 cm size, giving it a 12 cm HT with 57 cm ST (and 50.5 cm c-t ST / 74.5 STA). This is by far the closest I've found. Short ST, long TT, short HT. Angles look appropriate for mass start.

I saw the posts on the rear drop outs bending up a bit on the DF4. I don't know of any other issues.

I'd prefer a BB30 so I can use one of my SRMs but I am open to getting a BSA SRM if I can't find a BB30 frame with similar dimensions.

My current "aero style" frame (shod with training wheels). I'm no aero expert but I don't see if I can get too much more from the DF4, except perhaps in weight and rigidity (and UCI legalness). My frame is so small that it presents less to the air than, say, if I rode a 60 cm. I think the biggest gains will be from my position, my helmet, wheels, and wearing a skinsuit:
http://3.bp.blogspot.com/_TbmplkIYLx...0/DSC_0811.JPG

you've got pretty unusual dimensions, but for track racing, you're in luck. very long and very low is not uncommon in track frame geo - though this is largely designed around accommodating fairly tradtional aerobar setups (low) on large frames. A Dolan DF3, for example, has a 12cm headtube in a 57 frame size (I wrote that before I finished reading your post). There are certainly others, but I don't know them off the top of my head. Doubtless a few other people on here do.

You won't find a BB30 track frameset, full stop, unless you get one custom made.

If you wanted to get wild you could also look at modifying a road TT frame that has a very short headtube. That's not all that weird on the track (or rather, it's not common, but neither is it unusual).

I expect that you'll be able to find something that works - though you might need flexibility on your stack dimensions. Fortunately for you there is a wide variety of very deep handlebars that can still put your torso where you're used to having it.

There was a useful thread on this forum in the last few years that listed dimensions of dozens of track frames. Unfortunately I can't locate it; maybe some else could post the link.

I think this is it:
https://www.bikeforums.net/track-cyc...-registry.html

Thanks for encouraging me to look. I'll start there.

Aki, look at the DF4. It has a 57 TT and 12 HT. Don’t know about seat tube.

That is the frame that seems to check all the boxes. 50.5 c-t seat tube, which is tiny for a "57" frame, but fits my hobbit legs perfectly.

Hm Dixie Flyer seems good too. 58 TT, 12.5 HT, 52 c-t (a bit tall). Lose 2 cm TT length to go down a 50 c-t but also lose 1 cm HT length as well.

Would fifty Point one racing have something that fits? I like the fact their geo chart leads with stack and reach numbers.

https://fiftypointoneracing.com/geometry.html

It has been said before on this forum that reach and stack are more useful than just TT and HT length.

Also I believe it is Carleton who says track bikes need extra reach over ones road bikes.

Unlikely. They are not long and have nothing with a stack and reach close to the Dolan.

CDR’s road setup is more aggressive than most track sprinters.

Looks like their longest 12 cm HT frame is 55 cm TT, with a 74 STA. Although I don't have a reach number on my frame, the STA is 1.5 deg shallower with a 1.5 cm shorter TT, so it's probably a bit over 2 cm shorter than my road bikes.

However... what I found really interesting is that it looks like they use the similar tube set used to build my black bike. It's a stock aluminum tube set by Easton? I think, although I opted for external headset and a regular top tube. it sort of validates the idea of simply having an aero frame build for me, although such a frame would not be UCI approved. Which I don't think is an issue but still, it'd be nice to have the option / hope of needing to pass UCI inspection.

Jingers, I forget how long you need your bike to be, I thought the FUCI geo might be good for you but that's still 20mm shorter in the reach than the Dolan which keeps the 50cm seat tube.

I reached out to Dixie and of course they have a pre-order special right now.

50 cm ST, 56 TT, 11 cm HT
52 cm ST, 58 TT, 12.5 HT

I'm going to measure my bike (again) when I ride tonight. See what a 52 c-t looks like on my bike.

Good luck, Dixie will gladly charge your pre-order, but if you do get a bike, it’ll probably take forever or it will come with a variety of problems like mine did (messed up fork and steerer tube, uneven drop out spacing, etc.)

On the other hand, I know of many people who are very happy with their Dixie Flyer and happy with Bobby's service. I do not own a DF, but full disclosure Bobby is a friend.

The Felt TK1 could possibly fit the bill, too. The 57cm has a 57cm TT, 49.5cm ST (c-c) with an 11cm HT

And this, my friends, illustrates the dilemma that occurs when buying (or selling) "China Carbon": Fluctuations in quality control.

Most people will great product. Others will not. I saw the same thing happen with Serenity. I've seen first hand it happen with "VISP" budget aluminum frames.

Recall that YouTube video about how easy it was to start a bike company in China? Something like $5,000 and you were off and running?

The manufacturers will simply deliver stuff you wouldn't (shouldn't) sell, just to keep from wasting time and materials. These pass on into the hands of customers. It's so bad that one company in the video pays a U.S. employee to live there near full time to watch what comes out of the factory and make sure they aren't shipping crap across the ocean (which also costs $).

China Carbon it's necessarily bad. Just know that it's a gamble.

I'm at the commitment point. I rarely make large cycling purchases, and plunging into track will be my first big investment ($4000?) since 2008, and basically my largest ever purchase for bike equipment (In 2008 I spent $4800 on a new SRM equipped bike but recouped about $1000 selling stuff off of it). My focus is on the frame/fork/etc, the rear wheel, SRM (upgrade or something - I have one left), track drop bar, and track aero bars. I think I'll need a stem, maybe two, and I ought to get one more ISM saddle. And a set of training wheels, but I could lace over a rim onto my current good rear wheel (Suntour Superbe rear hub) and use whatever front wheel.

The decision is between the Dolan DF4 (57) and the Dixie Flyer (56), and I'm leaning heavily to one.

Dixie - I've exchanged a few emails with Bobby so I feel like there's a bit of personal investment there. On the other hand I feel like the frame isn't optimized overall, like I'd want a couple things changed. It's small stuff but remember, I don't think I'll ever buy another track frame, or if I do, it might be in 10 years. The frame is a bit shorter in length than my road bike, based on STA and TT length. Dixie is 74 STA, 56 TT.

(Reminder, my road bike is 75.5 STA, 56.5 TT, with a 14.5 stem, 12 cm reach / 8 cm drop bars.)

Dolan - The DF4 is the same price, within $20 (shipped) at the current exchange rate, so basically no difference. A couple key features really appeal to me - the aero seat post, the more integrated fit of the seat tube in front of the rear wheel, and the steeper STA and longer TT (74.5 and 57 respectively). It also seems a bit more complete, more engineered, compared to the Dixie.

My one concern with the DF4 is being able to get the saddle far enough forward - I'd want to be able to legally max out an ISM in the forward position, i.e. zero setback on an ISM. I'm not sure if that's possible, and it's not like I can use a different post. However, looking at the pictures, it looks like it'd be possible or at least very close.

I can check the zero setback question at the weekend if you wish? I use a spesh power, looks roughly about the same length as the ISM

I own a DF4, and while it's a great bike, mine took some fiddling to get it working. The seat post binder is an issue, you may have read about it. I have a PVC pipe down my seat the as insurance against slipping (and it was slipping at first). The latest seat post clamp has an insane torque rating thatI'd be afraid to apply to a bolt that size. I don't, and it combination with the PVC pipe, it's no longer moving. Also, I had some headset issues, now fixed. I'm really happy with it now, but it took some work to get it solid. The aero seat post is not even something I was looking for, but the price was too good to ignore.

From those I know who have the Dixie, the 56 is pretty short. Most people who would usually be on a 56 are on the 58 Dixie I believe. You should go by the reach figure in the geo chart rather than the top tube length with that bike.

I believe this situation has been improved greatly now with some revisions.

Unless something major has been done it's just a new binder assembly with a crazy torque rating. Any body have a year 2016 or later DF4 that can comment?

I appreciate the offer.

I'm looking at the pictures, I'll be using my old protractor up against my current frame to get an idea. I think it'll work, for sure it'll be at the limit.

I forgot, I'll be going 5mm shorter on my cranks so my saddle will go back 5mm relative to my current position.

Thanks for this feedback.

I felt the 56 was really short on the Dixie, I'd lose maybe 2 cm total reach, a significant amount when I'm already on a 145 stem. I contemplated the 58 but the c-t is 52 cm which I can barely straddle on a flat surface, forget about a sloped one with a downhill. It'd be nice to be able to clip out on either side and not worry about falling over.

The seat post thing... I'm okay with some fiddling but in the end I want a bike that's predictable. I don't want to be wondering if things will hold up when I make an effort. If it takes a short pipe or whatever, okay.

I haven't had issues with my seatpost slipping, and I have one of the older DF4s. I think the one big drawback to the current DF4 is the short track ends, but at least they don't spread.

I’ve now got multiple chains for this issue

I've taken the plunge and put in for the Dolan. Thanks everyone for all the help and thoughts, I'll be prepared with a PVC pipe, carbon paste, torque wrench, etc. Now to get a rear wheel, tires (?), bars, stem, another saddle, an SRM, and some minor stuff. I have a slew of (new) cogs, couple chains, chainrings with I don't think I can use (130 BCD, for when I was going to use a Campy crank as a track crank). I need to lace over a clincher onto a track hub since I don't have a clincher track rear wheel. And next spring some tests with different aero bars vs without, and some drives to velodromes to race the thing a big.

If you need chainrings or cogs - https://www.njs-export.com/ is a great source. (The eBay web store - link at the bottom of the page - is sometimes cheaper.)

And you really don't need an SRM if you're trying to save money. But if you do go SRM, you will probably want to go with a Rotor version to be able to go with arms shorter than 165, which I would assume is what you would want.

Thanks on the rings/cogs link.

SRM - they offer 160 now, at least on their site (Origin track), but believe it or not I'm going to start with 170 and see how it goes. Using a 175 on the road, I've had a hard time getting used to even a 170, having tried it 3 different seasons in the last 12 years or so.

I'm pretty vested in SRM, with two on my road bikes, so having a third would keep things consistent. I don't want to be wondering if the power reading is off from one crank to another. Plus I'd have spare heads, pickups, etc. And with trade in stuff I may be able to save some money.

What I meant was, you don't really need power on the track. It's definitely nice, and I have it, but just starting out, not really necessary. Also, IIRC, you are still running wired SRM head units. The newer ones are wireless. I don't know that they will work together. And if you opt for an older wired SRM, many of them are not weather sealed. This isn't an issue unless you travel with your bike outside your car.