SR400 frame: how modern can you go with components?

[SR400 -105]

Hi All I have had my SR400 since 1988. It still has the majority of the components that were on the bike when I bought it 105 and ultegra 600. This Sping I replaced the stem, saddle, bars and brake levers to very great affect in comfort and riding endurance. With the 53/42 front end and the 6 sprocket back end living in a flat place I do ok and many rides I do not even shift much. The old index shifting works OK it does the job. I love the frame.

I was thinking I wanted more without going new bike. The question is could I for example get 105 rx7000 to work on my 3.0 frame without much difficulty. I know anything is possible with enough effort and $$. I have read a lot on the new 105 and ultegra ( I current would not ever see myself riding enough to justify dura ace) and think adding some gears, a power meter crank, ( I like my SPD pedals and there are no good options there) would an 11 or 12 cog cassette on a new wheel even fit in the frame?

I understand bikes well enough to know what the parts do and to grossly fix something on the road. Going to guess that replacing the bottom bracket would be the biggest challenge as I think I have read there are limits to what will go into space that will support the modern components.

Plan B would be to go new bike (leaning Orca M20 or M30) and keep the SR as is for an occasional ride. Thanks for thinking on this and for any suggestions that may come.

 

[black lightning 1987]

First thing I would do is take the rear wheel out and measure the exact spacing between the dropouts. If it's in the 128-130 mm range, I'd think you would be OK running a 130 spaced wheel. I have spread a 1987 Cannondale road bike (nominally 126 mm I think) and ran a 130 spaced wheel for several thousand miles but it's not something I'd recommend.

Curious as to what you want to gain by going to current components. What don't you like about the bike now?

 

[SR400 -105]

First thing I would do is take the rear wheel out and measure the exact spacing between the dropouts. If it's in the 128-130 mm range, I'd think you would be OK running a 130 spaced wheel. I have spread a 1987 Cannondale road bike (nominally 126 mm I think) and ran a 130 spaced wheel for several thousand miles but it's not something I'd recommend.

Curious as to what you want to gain by going to current components. What don't you like about the bike now?

two things really one I would really like a power meter (crank not pedal as there are no SPD cleat pedals on the market right now) the second is better gear response and the idea of more gears is appealing. A more modern wheel with a wider tire option I could see as benefit also. That’s about it really

 

[black lightning 1987]

Are you wanting lower gears but OK with the current high gear? You could go to a compact, subcompact, or triple crank depending on what your desired range is.

I don't know a thing about power meters. I think you would get good info on them by posting on the paceline forum or bikeforums. Be sure to mention what gearing you are looking to get.

 

[SR400 -105]

Are you wanting lower gears but OK with the current high gear? You could go to a compact, subcompact, or triple crank depending on what your desired range is.

I don't know a thing about power meters. I think you would get good info on them by posting on the paceline forum or bikeforums. Be sure to mention what gearing you are looking to get.

‘not necessarily lower just better shifting and in between options. Power meters are not that hard hub, crank or pedal. Wheel set could work if it fits. I am pretty stubborn on not going back to LOOK so the easy option will not work for me. Crank requires modern equipment. Hence to see if anyone has upgraded or know if modern 105 would work.

 

[black lightning 1987]

Have you taken the wheel out and measured the droupout spacing?

 

[SR400 -105]

Have you taken the wheel out and measured the droupout spacing?

I need to do this when I have time. I may just go with a powerpod power meter which will work with my ride. It measures the indirect forces (wind,elevation,speed from the speed sensor) and calculates power based on that. Supposed to be accurate and it’s cost effective.