elmills81

I am working to repair a poorly shifting 2011 Jamis Aurora that I bought "new" in 2012. I thought I bought new, but the parts on the bike and the parts listed on the manufacturers website as stock are inconsistent. I rode this bike for several years consistently and it has ~3800 miles on it. It worked well for the riding I was doing and I generally have no complaints for what it is. In the last 2 years it has been ridden less than 250 miles per year, but am looking at using it for a GAP/C&O ride in October this year (conditions permitting) and am trying to get it back up to speed. I am looking for a smooth reliable ride with 15-20 lbs of additional gear on board. I have a true road bike for my smooth/dry pavement riding.

I started to take the bike apart because I was having some rough shifting and slipping at high power even after installing a new chain. In addition I have a grinding noise in the bottom bracket when pedaling hard on the left side. With further inspection of my chainring both the middle & larger rings have teeth that are worn unevenly, that are significantly different sizes. When I took everything apart I figured I would just look up part numbers and find the best deal on new parts. However, it appears this bike is an interesting mix on MTB and Road bike parts. I started to search for different combinations of parts and quickly ran into a great deal of confusion.

I am willing to change out what is necessary, but ideally would like to switch the least amount as possible, but being cost effective. No sense in replacing with identical if a better/more cost effective part is available.

I know that the BB is going to need to be replaced, but looking for some direction. What do people recommend will work with the shifters/derailleurs that I have? Hunt Ebay for a not to worn set of chainrings/BB? Would something like a Shimano Alivio FC-T4060 work as a replacement for the front chainring/Crankset?

Here is what is currently on the bike:

• Chain
  • Sram PC-951
• Chainring
  • FSA
  • Large WA182-48T
  • Middle WB082A-36T
  • Small WC034-26T
• Crankset
  • FSA Alpha Drive CK-725
• Cassette
  • SRAM PG-950, 9-speed: 11-28
• Bottom Bracket
  • FSA Powerdrive, 118.5mm spindle
• BB Shell Width
  • 68mm
• Rear Derailleur
  • Shimano 105 RD-5700
• Front Derailleur
  • Shimano Tiagra FD-4503
• Front Hub
  • Shimano Tiagra HB-4500
• Rear Hub
  • Shimano Tiagra FH-4500
• Front Shifter
  • Shimano Tiagra Triple ST-4503
• Rear Shifter
  • Shimano Tiagra ST-4500

dwmckee

Chain rings come new with some short teeth on the middle and large rings to facilitate shifting up from a lower ring. Maybe just take it into a shop and have them evaluate it for drivetrain wear, etc. and possibly for a tuneup. That could really save you $ by only replacing what is in need... If that is the first time you have replaced the chain you may have ridden it too long which winds up damaging the cassette and sometimes teh chainrings.

cyclist2000

That sounds pretty much like what is listed in the 2011 catalogue. FSA cranks, Tiagra drive train, 105 rear derailleur. The catalogue doesn't list the chain or cassette mfg.

elmills81

@dwmckee Thanks for taking the time to respond and to educate me. I didnt realize that there were teeth of different sizes on the chainrings. I will have to check to see if they are consistenly spaced . I will plan to go down to the LBS and have them review, but wanted to know my options before hand. They have a "second hand" corner that may prove useful as well if I know some options.

I have been checking chain wear with a guage ~500 miles and I replaced it the first time just short of 2000 miles and I knew it was due for another which is what I hoped would resolve the issues I was experiencing, but unfournately did not.

elmills81

@cyclist2000 I agree it mostly matches, what caused confusion for me was the FSA Alpha cranks with the 48/36/26 vs the listed Vero with 50/39/30 that is listed in the catalog. I obviously was able to pedal the bike just fine for several thousand miles so it seems to work just fine. Not sure if the catalog is wrong or the LBS that built it did something different due to a parts issue.

cyclist2000

Normally there is some fine print in the catalogue that states that they may change some of the components without notification. Or you may have gotten the crankset from the 2012 model because the FSA Alpha is on the the 2012. They may have been changing some of the components when yours was built.

cpach

If a new chain slips then its riding on worn teeth. It is considerably more common to wear out the cassette. Test ride the bike by riding in each gear combination and pedaling with the rear brake engaged and find out which combinations skips, which can illustrate if it's the cassette or if any of the chainrings are worn. Visual wear is not important--observed slipping is.

Also for shift performance you should definitely replace all the housing and cables and use a derailleur hanger alignment tool to make sure the derailleur hanger is aligned. Also eventually play can develop in the derailleurs that effects shift performance, although it would be very early given the mileage your bike has seen.

If the chainrings are OK I'd just replace the BB with another powerdrive BB, otherwise probably a Shimano crank like an Alivio would be great, with its matching BB.

Crankycrank

3800 miles is not really enough to wear out many parts other than the chain unless the bike has seen some really extreme conditions or very poor maintenance. It may just need a few adjustments and possibly new cables and housings as they can get corroded and gummed up over time rather than just miles. If you have an open Co-Op nearby take it there and get some advice on servicing your bike or check out the many videos available to walk you through everything.

elmills81

Thanks cpach . This is my first post on the forums after lurking for an extended period of time. I am really impressed with the level of knowledge sharing.

I will reinstall the parts this evening and test out with your suggested process. I appreciate you and the rest of the group dissuading me from just buying new parts and teaching me the way to maintain my own bike!

elmills81

I wanted to followup with this thread and thank everyone for the help/assistance. I received replacement cables in the mail yesterday and the tool I needed to remove the bottom bracket. I removed the bottom bracket and thoroughly cleaned the cassette, crankset, and derailleurs. Then went through the process to align the from derailleur and start from scratch setting up the rear derailleur. After doing this my skipping problem has gone away. I still have a slight groaning/grinding sound from the bottom bracket when applying maximum pressure (going up hill) and the shifting is not 100% smooth in all gear ratios, but it is MUCH improved. Still has some alignment challenges when in the middle chain ring rubbing against the larger chain ring, but only in the highest 2-3 gears.

I am going to put some additional miles on it, stretch the cables and then readjust. I do think the bottom bracket may ultimately need to be replaced, but the commenters on this post helped save me significant amounts of money versus just replacing everything and starting over.

cyccommute 

There are several teeth that have a different profile that aid in the lifting of the chain during shifts. The three red arrows in the picture below point to these special teeth. The blue arrow points to the lift pin. There are usually 4 lift pins (maybe only 3) on the chainring.

Untitled by Stuart Black, on Flickr

The chainring on the left shows what a worn chainring looks like. Your mileage shouldn’t have worn out the rings.

worn vs unworn by Stuart Black, on Flickr

cyccommute 

I’m glad everything worked out for you but for future reference, 90% of bicycle problems are related to cables. Check there first before removing any parts. The barrel adjusters on the derailer usually need just a minor twist to take up cable slack. It’s a lot easier then removing and installing all the parts.