Modify Racing Bike

Old 09-11-06, 09:06 AM
Visiting Guest
Posts: n/a
Talking Modify Racing Bike

I have a 25 year old Miata racing bike. It has racing handlbars, a hard seat and gear shifters on the down bar. The bike is in good condition and I like the way it rides but my back hurts too much to ride it. I went into two bike shops and asked them about replacing the handlebars with upright type, installing a more comfortable seat and relocating the shifters. Both shops felt the shifters should remain where they are. Both also said they can replace the handlebars and seat. However, one shop discouraged it beacuse they said the bike would not ride well because the center-of-gravity will be different.

I would like your opinion as well as the pros and cons on making these modifications. Thanks.
Old 09-11-06, 10:59 AM
Join Date: Nov 2002
Location: Northern Virginia
Posts: 819
Upvotes: 0
Received 26 Upvotes on 23 Posts

For a minute there I thought you were going to want *facts*. Opinions are easy!

Kidding, of course. The bike should reflect the type of riding you'll be doing: in its racing bike configuration, the hard seat, "drop" handlebars, and downtube shifters make sense because a racing rider wants a low profile to reduce wind resistance.

Does your back hurt with this bike only, or has it been a while since you rode any bike? My back always hurts the first few rides of the season or when I've been away from riding for a while, and I am healthy, in tolerably good shape, and my bicycle fits me properly. So the "back hurts" problem may present itself regardless of bicycle or seating style, and may resolve itself after you ride a few times as your back muscles get used to the idea of cycling.

As for your modifications, the type of riding you want should dictate the bike you ride. More comfortable seat on a racing frame should not be a problem; upright handle bars should not be a problem; placement of the shifters may be too tricky to fuss with. Older bikes have downtube shifters (again because the rider is already in a tuck position) with threaded ports on the outside tube surfaces to attach the shift levers. The bike shops you spoke to may have suggested leaving the shifters in place because they work and are already there, or to save the expense of new shifters, or because of incompatibility between new shifters and old derailleurs. (Bike shops *should* have parts sources for any conceivable type of bike, however. A good source of parts for older bikes, just in case, is ) If you're looking for a more upright seated position, I don't know of a reason not to go to updated shifters that mount on the handlebar and thread the cables through cable guides where the shifters are now. The bike shops have seen the bike, though, and they may have a specific reason to recommend the shifters stay where they are.

If you stay with this frame but go to a more upright seated position, you may find shifting inconvenient if the shifters are located on the downtube. It will likely be a bit of a reach.

As for this center of gravity thing, (Warning! Editorial content follows!) I don't know that sitting a little more upright would change the center of gravity so substantially that it would materially affect the riding characteristics of the bike. But again, the bike shops saw you and the bike, and they may have a very specific reason to say that. (For instance, was the next sentence "Let me show you the 2007 line of Spiffarino bikes! Financing is available!"?)

Probably the single most critical aspect of cycling is "fit": matching the rider to the bike and adjusting the components on the bike to fit the rider. This is for comfort, efficiency in the transfer of power, and to avoid damage to your joints and connective tissues. If you're intent on keeping this frame (and there's no reason not to, if it's mechanically sound) go to the shop that did not give you the center of gravity speech and ask "If I make these modifications to include new seat, new handlebars, and new shifters , will this bike fit me properly? Will it fit me properly if I leave the shifters on the downtube? Will it throw off my center of gravity?" You should also say "I want to ride this bike (pick one all day every day / every now and again on nice days / two or three times a week for an hour / whenever the mood hits me / etc. Give me an honest appraisal: are these modifications worthwhile?" The right bike shop will give you these answers.

Here's my usual spiel about bike shops:
a) Don't go on a beautiful Saturday morning to get your bike fixed- EVERYONE wants their bike fixed immediately, and they will ALL likely be disappointed.
b) It's not unusual for the mechanic to ask you to leave it for a week.
c) It's smart to call and ask when the shop is least busy- go at that time, and get their best attention.

Good luck with it, and let us know how it goes!

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: