|Looking for bike with long top tube||Roadfrog|
Dec 14, 2001 3:00 PM
|I have a long torso and short legs which can be frustrating in trying to find a bike that fits. I know the Trek OCLV has a longer top tube but I want something different. Any suggestions would be helpful. Thanks, HOP|
|Hampsten bikes have a long top tube [nm]||davidl|
Dec 14, 2001 3:21 PM
|Tommasini, Merckx, Moser, Ciocc, Waterford, Rossin, suggestion:||Dog Breath|
Dec 14, 2001 4:29 PM
|There are no doubt others.
Deduct 1 1/2 cm from frames measured center to top to arrive at their c-c seat tube measurement, for comparison purposes.
Go to the Bullteksports.com site and browse through his frame selection. He has the geometries listed. Don't buy there though, he is pretty much full retail on everything and doesn't keep them in stock.
|caution with recommendations||Jack S|
Dec 14, 2001 4:44 PM
|What you really want is a slack seat angle and really long top tube, or normal seat angle and long top tube... most people don't consider this when making recommendations- they just look at tope tube length. Stock bikes that have long top tubes tend to have slack seat angles, making the fit not much different than a bike with a "normal" top tube and seat angle.|
Dec 14, 2001 5:04 PM
|It's not as simple as getting the bike with a long TT, because that usually is offset by a slack seat tube angle.
Listen to Jack S! Good luck with your search, and don't rule out custom. Some great custom steel frames out there for reasonable prices.
|Seat Setback||Dog Breath|
Dec 14, 2001 7:22 PM
|In an approx. 53 c-c frame with 73.5 seat angle (Tommasini, Merckx, Moser), the seat setback is only 3mm greater than a 74 degree frame. The Ciocc and Rossin both have the more common 74 degree seat tube.
Assuming the rider will be sliding the saddle ahead further with a 73.5 frame, the effective top tube is shortened by a max. of 3mm over a 74 frame in this size. Some riders already have the seat pushed back as far as it can go with the 74 seat, going to a 73.5 angle may benefit them powerwise, and will not reduce top tube length at all, or as much.
Most frame makers publish seat setback, which can be used to compare top tube lenghts (without taking into account possible differences head angles).
Dec 14, 2001 8:31 PM
|A typical rider on a 53cm frame will have a 82 cm inseam and a 71.5 cm saddle height. The set back difference at the saddle between a 73 and 74 degree seat tube angle will amount to approximately 12.6 mm. This amount offset is not insignificant.|
|your math is off...||C-40|
Dec 15, 2001 10:43 AM
|To calculate the change in effective top tube length due a change in seat tube angle, the difference in the saddle position must be calculated.
For the 53cm c-c (or 54.5cm c-t) frame of your example, a typical rider would have an inseam of 54.5/.67 = 81.3cm. The saddle height would be approximately .883 x 81.3 = 71.8cm. The difference is effective seat tube angle is calculated as (cos73.5-cos74)x 71.8 =.6cm. This is twice the amount of your estimate.
A good average figure is 1.2cm per degree. The actual amount varies from 1.0 to 1.5 depending on the frame size.
Dec 15, 2001 8:03 PM
|It's Sin, not Cos to calculate the setback.|
|Little length difference...||C-40|
Dec 15, 2001 6:54 AM
|Tommasini top tubes are not longer than the majority of brands. Neither are Waterfords.
If you do an accurate analysis, it's rare to find frames that differ more than 1cm in effective top tube length, except perhaps at the extreme ends of the size range. Midsized stock frames run in a very narrow geometry range.
|Crunch some numbers||Prince|
Dec 14, 2001 5:52 PM
|To determine whether you need a longer top tube first determine you arm length + torso length.
Post your reply, we'll take it from there.
Without these two dimensions you're riding nowhere.
|You might try a Thomson setback seatpost, too. nm||Elefantino|
Dec 14, 2001 5:57 PM
Dec 15, 2001 7:13 AM
|Pushing the seat back will only screw up the seat to BB relationship.|
|re: Looking for bike with long top tube||sscrosser|
Dec 15, 2001 12:58 AM
|You can also look at custom. They are not more than any of the other bikes listed here, and would be far better for you if considering the troubles you seem to be having. I know Curtlo makes some nice stuff for not that much, and you can also check ou Soulcraft, Sycip, Independent, Gunnar, Steelman, Landshark, Sibex, etc. There are more but those are just off the top of my head. None are more expensive than an OCVL, and you'll get just what you are looking for. Also, Lemonds have infamously long top tubes and real slack seat tubes. Check them out too. Good luck.|
|Lemond geometry pretty standard now....||C-40|
Dec 15, 2001 6:57 AM
|Must have been abandoned recently. The current geometry charts list some pretty ordinary angles and top tube lengths.|
|whatchoo talking about?||homiegee|
Dec 15, 2001 11:38 AM
|I don't know what bikes you are looking at, but Lemonds are famous for their slack seat tubes and long top tubes. Their top tubes are longer than the seat tubes, and their seat tubes are as slack as 'cross bikes. Just looking at the 60, the tt is 61, and the seat angle is only 72. I don't know of any production bikes that shallow-the longest 60's are usually only 60 tt and 72.5 or 73 seat tube. In any case...|
Dec 15, 2001 2:21 PM
|The 53cm (c-c) Lemond frame has a 73.25 degree STA and 54.5 TT which is pretty standard stuff compared to most 54 or 55cm frames measured c-t.
The current geometry chart lists a 61cm (c-c) with a 72 degree seat tube angle and 60.5 TT. This frame would measure about 62.5cm (c-t). In this large frame a STA of 72 or 72.5 is pretty common.
A 63cm Litespeed Classic for instance, has the same 72 STA and a longer 61cm TT.
A 61cm Litespeed has identical geometry to the 59cm Lemond.
If you aren't aware, shallow seat tube angles actually shorten the effective top tube length. To compare the TT length of a large frame with a 72 degree STA to one with a 73 degree STA, you should subtract 1.5cm from the length of the TT on the frame with the 72 degree STA.
|re: Looking for bike with long top tube||gusriley|
Dec 16, 2001 7:56 PM
|Check out an Aegis Aro Svelte. The top tubes of them tend to be longer because the seat tube bends back. Nice bikes. http://www.aegisbicycles.com/|
|wow- didn't get any of above!||nm|
Dec 17, 2001 6:13 AM