cisaksen

MRT2

Honestly, it might be more trouble than it is worth. To go to 11 speed, you will need new brifters, a new cassette, new back wheel, a new rear derailleur, and a new chain. Plus labor, unless you have the skills to do the work yourself. Just spitballing here.

105 brifters - $200
11 speed cassette - $60
Chain - $35
Rear derailleur - $50
Back wheel - $150
Misc - cables, cable housings, bar tape, etc, -$60
New crankset or chainrings (maybe) ?

As I said, just spitballing, but you are at or over $500 in parts alone. Maybe you can get better deals, and bring the parts cost down a bit, but then again, maybe not. If you are paying someone to do the work, figure another $100 to $150 in labor so you are now at $650 or so. Upgrading to 9 speed would be a lot cheaper, but oddly, in some ways you are downgrading since you are talking about switching from old 105 to new Sora level gear. And, 8 to 9 speed isn't all that much benefit. Honestly, I would just stick with 8 speed and start saving for another bike.

52telecaster

10 speed would be cheaper than 11 but honestly 8 is pretty darn fine anyway.

Point

Agree - nothing wrong with 8 speed. With 10 you may get a few more useful gears, also may find more duplicates.

Koyote

If you're going to upgrade, go with an entire new groupset...It'll be cheaper than buying parts piecemeal.

But as others have noted, 8-speed is good stuff. I have 9, 10, and 11 speed bikes, and the numbers of gears is a non-issue when choosing one for a ride.

mstateglfr 

are you wanting to change because components on your current setup are wearing out?
it makes sense to upgrade if this is the case because you need to buy components regardless and so why not upgrade.

If you dont need to swap out worn out components, you may not get much benefit in upgrading.
the one big benefit would be more appropriate gearing as a current crankset comes in 50/34. And make it easier to climb hills vs your current setup. You could just buy a new crank though too and get that gearing change.

if you go to 11sp, you need a new wheelset in addition to all the components.

Ironfish653

MRT2's estimates seem about right. Most people don't realise how much components cost, and how little compatibility there is between 11-speed and older generations.
If you do save up, and chase down good deals, piece together your 11-speed set, then you've still got most of a 20-y/o alloy Trek.
Do that, and you've spent about as much as it would take to buy a 3-4 year old 10-speed bike.
I have a local CL seller (can't tell if it's a shop, or just a hobbyist) who handles a lot of mid-high end road bikes. For the cost of your upgrade, you could be in to a much newer machine. (his 10-speed 105 bikes seem to go for ~$600) Then, you can sell your old bike complete, and make back a couple hundred from the purchase.

MRT2

But on a positive note, if OP wants to keep his bike as an 8 speed, replacement parts are downright cheap.

Ironfish653

Clem von Jones

I'm converting my 8 speed to 9, mainly because the cassette selection for eight speeds is now inadequate. Eight speed cassette selection was good a few years ago when I created this build but now 9 speed seems to be "the new eight speed". Why only a 9 speed upgrade? Because I can keep my crankset, front and rear derailleurs. I only need to change the brifters (to microshift 9 speed for $75), new chain, and cassette (which are due for replacement anyway).

My upgrade decision process involved looking carefully at all the various cassette choices in various speeds. If you're satisfied with the current ranges of 8 speed I would just stick with it. There's nothing wrong with 8 aside from that.

jgwilliams

Since nobody has mentioned this to the OP, the main reason it would be cheaper is that Shimano compatible freewheel bodies are compatible between 8, 9 and 10 speed, so you could use the same wheel. If you go to 11 speed you'd need to change the wheel. I doubt you'd need to change the chainset so what you're looking at is brifters, cassette, chain, rear derailleur and bar tape. I would assume that all the cables you need will come with the brifters - they do with Campag gear. There are certain wheels which allow you to change the freewheel body only over - notably Mavic - between Campag, Shimano 8/9/10 or Shimano 11. I'd be surprised if you have one of those, though.

Viich

9 or 10 speed ( as long as you stay away from Tiagra 4700) you can keep the same wheel , derailleur, etc. Makes it cheaper, but you are into used parts. And I have 8sp 105 (1056) with dt shifting on my most used bike. I have another bike with 10sp 105 (5700). I like the 1056 better - shifts extremely cleanly.

52telecaster

+1

lalibertef

Hello
I am stuck like you. 8 speeds only. HOWEVER !!!! important for you: does you frame allow for wide cassettes like 10 or 11 speeds? My frame width does not allow for anything more than 8 speed.