TNRazorbacker

I have a 2005 Trek 2100 bought new in 2005. I upgraded the Drivetrain and shifters to 10 Speed Ultegra about 15 years back. I pulled it out of storage a couple of years ago (2022) to start riding again. I put a new set of 10 speed 105 shifters on it then and added a set of Superteam carbon wheels last year. I like the bike. It's in great shape and rides good. I'd like to have upgrade the components for smoother shifting and more gears though (particularly for climbing) though.

Question, I'd like to upgrade the bike to a modern drivetrain. Maybe a 105 Di2 setup. Is this possible with the bike of this age? If so does it make sense from a cost perspective?

thanks

Iride01 

Shimano 105 Di2 is 12 speed and hydraulic disc brakes only. Does your old bike have disc brakes and a 142mm rear spacing? Perhaps a 12 speed cassette can work on a bike with less OLD between the rear. But the big thing is whether or not you can fit hydraulic discs on it.

I think the older Ultegra Di2 had a rim brake Di2 STI. Still, no matter how much you like your bike, I'd just get a new bike with Di2 on it already so any of the gotcha's were found and dealt with by the bikes manufacturer before they put it out for market.

Welcome to BF

TNRazorbacker

It has the original rim brakes. How would I confirm the rear spacing just measure between the inside of the fork?

FBinNY 

Yes, remove the rear wheel and measure between the inside of the dropout faces.

Retrofitting disc brakes to this is not a practical option. So start by seeing Shimano's most recent Di2 rim brake groups and see if there's something that meets your goals. Then only you can decide if it's worth the cost.

Iride01 

Hopefully the fork is on the front of your bike. You need to measure the rear spacing between the dropouts. Easier if you remove the rear wheel. Or measure the distance between the lock nuts on that rear wheel.

Still, even older Ultegra is going to be expensive in just parts alone. If you can do the work yourself, it might be worth it. But only slightly. You'll eventually find out it doesn't make you any faster or the bike ride any better. You'll just have the novelty and slightly less routine maintenance required. But you'll have a big wallet busting potential when most any Di2 component goes bad.

Don't get me wrong, I like Di2. But it will not make you any better a rider than you are.

It about the same conclusion I came to after taking a 1991 Schwinn Paramount and putting all new Shimano 11 speed 105 5800 components on it circa 2016-2017. I really enjoyed the bike, but it wasn't any lighter or faster. So I got rid of it and got a new 2020 bike with Ultegra Di2. And that 2020 bike is so much more fun to ride. But not because of the Di2. I will have been just as happy with mechanical shifting.

Steve B.

The upgrade to electronic shifting is a bit easier with SRAM. The shifters, like the Ultegra and Durace Di2 shifters are wireless. Unlike the Shimano systems, the SRAM front and rear derailers have their own batteries, so no wiring needed between components. With Shimano, you would have a battery inside the seat post, then 2 separate wires, one to the front derailer and one to the rear. That wiring needs openings in the frame in order for the e-tube connector to get to the derailers. You might find yourself drilling holes in the frame for the wiring. Thus SRAM is simpler, if you are OK with the shift system, which is not how Shimano works.

shelbyfv

An easy and inexpensive solution for easier climbing gears would be a GRX 46-30 crank. It will work with your existing components with the possible exceptions of front derailleur and bottom bracket.

veganbikes

So Di2 is doable but you will have to find older 11 speed stuff to make it work with rim brakes. In the end while Iove love love Di2 like truly love it I would rather keep that bike as is and buy something new with 105 Di2. Though I believe in having multiple bikes and having a beater bike you can have fun with or take on trips is a good thing and then having a nice new bling road bike would be fun.

TNRazorbacker

Oh I have no doubt that I’d enjoy a new bike better but I get a bad case of sticker shock looking at comparably outfitted new bikes. Yikes 😁

I don’t expect to get a lot faster with the upgrade, just a bit better performance over a long ride. I’ve test ridden some Di2 bikes and there was definitely a difference in that regard, (at least from my perspective).

TNRazorbacker

Thanks, I hadn’t really thought about SRAM as I’ve always used Shimano. I will check this out. Isv there a lot of difference to adjust to in how it functions?

Steve B.

AFAIK there some weird/different stuff about L shifter doing cassette up shift, R shifter doing down shift or some such. Not really sure and with electronic you can usually configure how the shifters do things if I recall, maybe others can chime in.

Barry2 

I can see where this is going.



+1 for Shimano

veganbikes

I will preface this all with I generally bleed Shimano Blue and love Shimano a lot.

SRAM AXS is generally great at least function wise (my set up has been a bit wonky but that is not all on SRAM). Essentially one lever to up shift and one to downshift and then hit both to shift at the front which is easy (mine is 1x so no need for front shifting). The "Urkelnomics" (-Michael Scott) are really nice on SRAM levers I have used their single speed levers for a long time and they are very comfortable and essentially they are their normal doubletap levers without shifters. Shimano doesn't really offer modern single speed levers (aside from a 1x left side) and while the old school stuff looks nice it doesn't feel as good. The wireless aspect of AXS is great as it was pretty much install and install shifter pair and done. No cabling no wires and a pretty easy to use app. Though in my case I have wires but that is because I wanted to run a Zirbel Shifter and Clics but I am doing an oddball flat bar set up.

Had Shimano come out with XTR or XT Di2 12 speed I would have gone with that in a heartbeat though the Zirbel is really really nice (but expensive) but since they haven't and we are still waiting I am happy with the choice I made so far.

However saying all of this 12 speed might be tough with classic road spacing. Mainly finding a proper 12 speed cassette that will work in a 130 spacing and hopefully with a standard S-group free hub might be tough. I know it exists on the MTB and Gravel end but an 11-32 say for road might be tougher as I recall those didn't exist but I could be wrong and unfortunately I don't have access to my normal vendors to double check quickly and easily.

PromptCritical 

You would probably have sticker shock at the upgrade too. I got a quote for a similar upgrade and it was $4,500.

I had similar era (‘05 or ‘06) Trek Madone. It had a triple crankset. (3x10 Ultegra) Really helped in the climbs.

That’s any easy retrofit.

Polaris OBark

If it is quick release and rim brake, it is almost certainly 130mm. (Disk brake quick release is 135mm, disk brake thru axle is 142 (but actually the same width), boost is 148, super-boost is bigger still ...). I think it is impossible, or nearly so, to find a 12 speed hub compatible with quick release.

jgwilliams

The downside of SRAM is that you need an XDR freehub, unless you're planning to go with Shimano cassettes. Would that work? SRAM uses 10 teeth for the smallest sprocket, compensating by using a smaller chainset. I presume the idea is to reduce weight.

BTinNYC 

TNR,
The rim brakes make the upgrade to Di2 a bridge too far. For those TN mountains, I would go with a 10 speed Medium cage 105 RD, and a 11-34 cassette. Maybe a new longer chain if needed. $125-$150

Iride01 

Better performance over a longer ride? I don't quite know what performance you are talking about. My cable pulled 11 speed 105 5800 shifted, IMO, as well or better than my Di2 Ultegra. I particularly liked the mechanical shifting's fast response to get the rear to move the needed two or three sprockets when performing a front shift. And I have my Di2 set to shift as fast as it can. But the mechanical beats it every time to complete shifts. The place where Di2 and I'd suppose other electronic shifting excels is for the less routine maintenance. Essentially none other than keeping it clean.

Don't let sticker shock on the new bikes deter you if you have the means to purchase it and be but only a ripple in your financial situation. The right new bike with Di2 or other electronic shifting will be so much better than the difference you'll see putting it on the old bike that you already upgraded once before.

zacster

I foresee a future where it is cheaper to make a derailleur that is battery powered and cheaper to make a shifter with simple buttons, rather than all those cogs, pawls, and whatever they use internally, all connected using an open wireless protocol, and everything is programmable with your phone. It will be backwards compatible back to the old 5 speed too since you set the spacing and it just moves that amount at the click of the button. It will know the range of the chainrings and cogs and will know its own mechanical range and shift accordingly. SRAM is getting closer to this but Shimano needs to catch up.

PromptCritical 

The SRAM 900 hub has an XDR driver (not sure if it also comes in an XD version) and a variety of widths, including a QR135 version.

TNRazorbacker

Forgive my ignorance, but are you saying that there is potentially an adapter that would allow 12 speed SRAM to work on an older bike?

Polaris OBark

It is a disc hub that can fit a frame designed for disc brake QR (135 mm spacing), so it is unlikely to help you.

PromptCritical 

Depends on what the frame is made of. 5mm from 130 to 135mm in dropouts is trivial if the frame is steel. If it is carbon, I wouldn't touch it. Aluminum, maybe.

TNRazorbacker

Aluminum frame but carbon front and rear forks.

FBinNY 

What matters is what you're working on. For these purposes, the rest of the frame might as well be another bike.