Trek 920 build up notes
11-16-16, 08:49 AM
#1
Pokemon Master
Thread Starter
Trek 920 build up notes
I've been a bike shop mechanic for about 10 years now, so I thought I would give you guys some of the mental notes I took while I was building my personal 920. Just kind of a "things to watch out for" kind of write up, not an in depth "this is how you build a bike from a box" thing. I don't go on long trips, but two or three 3-5 day trips per year isn't abnormal for me. This bike will mainly be my commuter and grocery getter.
1) SIZE THE FRAME ON TOP TUBE LENGTH, NOT SEAT TUBE! The stock stem length on all of the 920 sizes is ridiculous. When you look at the geo chart, the 56 (what I normally ride) has a 100mm stem (what I normally ride) but the top tube is 57.8cm long. My 2012 Tricross Sport is 56cm square, and it came stock with a 100mm stem. It's comfortable. The 920 combination of long top tube, long stem, and ridiculously long TRP brake hoods makes this bike feel like a limo. I came into this purchase knowing these things, and also knowing the bars and brake/ shifters were going to be replaced almost immediately. If you're planning on buying a 920 and immediately setting out on a 3,000 mile tour; size the bike on top tube.
2) Your spokes are loose. When the bike comes out of the box, the spokes are loose. The wheels were basically true and round, but tension wasn't as high as I like to see, especially when this bike has been getting lambasted for being an adventure bike with "only" 28 spokes. I think it's a bad idea, and I'm probably going to end up building a 36 hole rear wheel at some point. I also see no evidence of any spoke prep or linseed oil, which is fine by me. I'll do some measuring at work to see if NDS and DS are the same length. I'm hoping they are. Asymmetrical rims are awesome.
3) Your bottom bracket needs faced, and the bottom bracket cups have no loctite on them. I like using the bottom bracket facing tools, so it wasn't a pain for me to remove the BB and face it. It came out of the box decently square, but the paint wasn't uniform thickness around the face. I went very slow and pulled the tool off about every 1/4 turn (Chris King facer with 5 cutting heads, it works pretty quickly). Once I got through the paint, the actual frame itself was faced about 80% around. There was one low spot about 5mm long on the drive side, and a smaller low spot on the NDS. The cranks spun fine, but I felt much better knowing my bike was 100% when I got done with the facing tool. I also stripped the grease off the bottom bracket cup threads and applied loctite 243. We can go around and around about putting loctite on a bottom bracket (especially aluminum cups in an aluminum frame), but the manufacturer, park tool, and barnett's manual all recommend it. It does a great job of keeping the threads pristine, is easy to remove since it's a blue loctite, and it keeps the creak away forever if you install the bottom bracket correctly. I can't say the same for grease or anti-seize, which both wash out in use.
4) The rack bolts don't have loctite on them, either. In a world where almost every bolt on a bicycle comes with pre-applied loctite, I was really surprised to see none on the rack bolts. It was a simple fix for me, but I know most mechanics won't go to the trouble of applying loctite, especially if they're building the bike as a floor model, and not as a special order for a known customer they like. It sucks, but that's how it goes.
5) My stem top cap had been overtightened before it was boxed. there's stress marks all around the outside edge of the cap, right above where the top of the stem sits. there's even a mark where the slot in the stem is. Trek is going to warranty this for me, but it is still something to note.
That was all of the big items I noticed. Anything beyond this is just me being nitpicky, which is easy for me to do.
6) The housing loop on the rear derailleur was too long. It worked fine, and probably wouldn't have gotten caught on anything, but I cut mine about 2 cm shorter. It follows the chainstay much closer now.
7) The cables and housing for both derailleurs seemed to have a lot of stretch. For most builds, I run the barrel adjuster all the way in, pull the cable tight, and tighten the pinch bolt. Then I run the RD up to the largest cog, find an exposed bit of cable, and give it two good pulls with my thumb against the frame and my fingers around the cable. I run the RD down to the smallest cog, loosen the pinch bolt, pull the cable tight, and retighten. I do this until I stop getting slack when the RD comes down to the smallest cog, then adjust the indexing. It usually takes 1-2 pulls, but I did 4 on the 920 RD and my shifting still came out of whack on my 8 mile ride home. It was just 1/2 - 2/3 of a barrel adjuster turn, but it seems kind of excessive to me. I'm putting Jagwire Road Pro XL cables and housing on it when my Apex shifters and TRP Spyre brakes get in, so I'm not too concerned.
1) SIZE THE FRAME ON TOP TUBE LENGTH, NOT SEAT TUBE! The stock stem length on all of the 920 sizes is ridiculous. When you look at the geo chart, the 56 (what I normally ride) has a 100mm stem (what I normally ride) but the top tube is 57.8cm long. My 2012 Tricross Sport is 56cm square, and it came stock with a 100mm stem. It's comfortable. The 920 combination of long top tube, long stem, and ridiculously long TRP brake hoods makes this bike feel like a limo. I came into this purchase knowing these things, and also knowing the bars and brake/ shifters were going to be replaced almost immediately. If you're planning on buying a 920 and immediately setting out on a 3,000 mile tour; size the bike on top tube.
2) Your spokes are loose. When the bike comes out of the box, the spokes are loose. The wheels were basically true and round, but tension wasn't as high as I like to see, especially when this bike has been getting lambasted for being an adventure bike with "only" 28 spokes. I think it's a bad idea, and I'm probably going to end up building a 36 hole rear wheel at some point. I also see no evidence of any spoke prep or linseed oil, which is fine by me. I'll do some measuring at work to see if NDS and DS are the same length. I'm hoping they are. Asymmetrical rims are awesome.
3) Your bottom bracket needs faced, and the bottom bracket cups have no loctite on them. I like using the bottom bracket facing tools, so it wasn't a pain for me to remove the BB and face it. It came out of the box decently square, but the paint wasn't uniform thickness around the face. I went very slow and pulled the tool off about every 1/4 turn (Chris King facer with 5 cutting heads, it works pretty quickly). Once I got through the paint, the actual frame itself was faced about 80% around. There was one low spot about 5mm long on the drive side, and a smaller low spot on the NDS. The cranks spun fine, but I felt much better knowing my bike was 100% when I got done with the facing tool. I also stripped the grease off the bottom bracket cup threads and applied loctite 243. We can go around and around about putting loctite on a bottom bracket (especially aluminum cups in an aluminum frame), but the manufacturer, park tool, and barnett's manual all recommend it. It does a great job of keeping the threads pristine, is easy to remove since it's a blue loctite, and it keeps the creak away forever if you install the bottom bracket correctly. I can't say the same for grease or anti-seize, which both wash out in use.
4) The rack bolts don't have loctite on them, either. In a world where almost every bolt on a bicycle comes with pre-applied loctite, I was really surprised to see none on the rack bolts. It was a simple fix for me, but I know most mechanics won't go to the trouble of applying loctite, especially if they're building the bike as a floor model, and not as a special order for a known customer they like. It sucks, but that's how it goes.
5) My stem top cap had been overtightened before it was boxed. there's stress marks all around the outside edge of the cap, right above where the top of the stem sits. there's even a mark where the slot in the stem is. Trek is going to warranty this for me, but it is still something to note.
That was all of the big items I noticed. Anything beyond this is just me being nitpicky, which is easy for me to do.
6) The housing loop on the rear derailleur was too long. It worked fine, and probably wouldn't have gotten caught on anything, but I cut mine about 2 cm shorter. It follows the chainstay much closer now.
7) The cables and housing for both derailleurs seemed to have a lot of stretch. For most builds, I run the barrel adjuster all the way in, pull the cable tight, and tighten the pinch bolt. Then I run the RD up to the largest cog, find an exposed bit of cable, and give it two good pulls with my thumb against the frame and my fingers around the cable. I run the RD down to the smallest cog, loosen the pinch bolt, pull the cable tight, and retighten. I do this until I stop getting slack when the RD comes down to the smallest cog, then adjust the indexing. It usually takes 1-2 pulls, but I did 4 on the 920 RD and my shifting still came out of whack on my 8 mile ride home. It was just 1/2 - 2/3 of a barrel adjuster turn, but it seems kind of excessive to me. I'm putting Jagwire Road Pro XL cables and housing on it when my Apex shifters and TRP Spyre brakes get in, so I'm not too concerned.
11-16-16, 09:41 PM
#2
Banned.
Join Date: Nov 2015
Posts: 2,077
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 760 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
I'll keep all that in mind when maintenance comes up. I agree that it should come with brake lever shifters. Since I'm not young any more I'm getting shorter and ordered mine a size smaller. I'm comfortable on it, but I also have long arms. So far the wheels are fine.
Thanks!!
Thanks!!
11-23-19, 06:50 AM
#3
Newbie
Join Date: Aug 2014
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Keen in learning more on 920's bottom bracket
I've been a bike shop mechanic for about 10 years now, so I thought I would give you guys some of the mental notes I took while I was building my personal 920. Just kind of a "things to watch out for" kind of write up, not an in depth "this is how you build a bike from a box" thing. I don't go on long trips, but two or three 3-5 day trips per year isn't abnormal for me. This bike will mainly be my commuter and grocery getter.
1) SIZE THE FRAME ON TOP TUBE LENGTH, NOT SEAT TUBE! The stock stem length on all of the 920 sizes is ridiculous. When you look at the geo chart, the 56 (what I normally ride) has a 100mm stem (what I normally ride) but the top tube is 57.8cm long. My 2012 Tricross Sport is 56cm square, and it came stock with a 100mm stem. It's comfortable. The 920 combination of long top tube, long stem, and ridiculously long TRP brake hoods makes this bike feel like a limo. I came into this purchase knowing these things, and also knowing the bars and brake/ shifters were going to be replaced almost immediately. If you're planning on buying a 920 and immediately setting out on a 3,000 mile tour; size the bike on top tube.
2) Your spokes are loose. When the bike comes out of the box, the spokes are loose. The wheels were basically true and round, but tension wasn't as high as I like to see, especially when this bike has been getting lambasted for being an adventure bike with "only" 28 spokes. I think it's a bad idea, and I'm probably going to end up building a 36 hole rear wheel at some point. I also see no evidence of any spoke prep or linseed oil, which is fine by me. I'll do some measuring at work to see if NDS and DS are the same length. I'm hoping they are. Asymmetrical rims are awesome.
3) Your bottom bracket needs faced, and the bottom bracket cups have no loctite on them. I like using the bottom bracket facing tools, so it wasn't a pain for me to remove the BB and face it. It came out of the box decently square, but the paint wasn't uniform thickness around the face. I went very slow and pulled the tool off about every 1/4 turn (Chris King facer with 5 cutting heads, it works pretty quickly). Once I got through the paint, the actual frame itself was faced about 80% around. There was one low spot about 5mm long on the drive side, and a smaller low spot on the NDS. The cranks spun fine, but I felt much better knowing my bike was 100% when I got done with the facing tool. I also stripped the grease off the bottom bracket cup threads and applied loctite 243. We can go around and around about putting loctite on a bottom bracket (especially aluminum cups in an aluminum frame), but the manufacturer, park tool, and barnett's manual all recommend it. It does a great job of keeping the threads pristine, is easy to remove since it's a blue loctite, and it keeps the creak away forever if you install the bottom bracket correctly. I can't say the same for grease or anti-seize, which both wash out in use.
4) The rack bolts don't have loctite on them, either. In a world where almost every bolt on a bicycle comes with pre-applied loctite, I was really surprised to see none on the rack bolts. It was a simple fix for me, but I know most mechanics won't go to the trouble of applying loctite, especially if they're building the bike as a floor model, and not as a special order for a known customer they like. It sucks, but that's how it goes.
5) My stem top cap had been overtightened before it was boxed. there's stress marks all around the outside edge of the cap, right above where the top of the stem sits. there's even a mark where the slot in the stem is. Trek is going to warranty this for me, but it is still something to note.
That was all of the big items I noticed. Anything beyond this is just me being nitpicky, which is easy for me to do.
6) The housing loop on the rear derailleur was too long. It worked fine, and probably wouldn't have gotten caught on anything, but I cut mine about 2 cm shorter. It follows the chainstay much closer now.
7) The cables and housing for both derailleurs seemed to have a lot of stretch. For most builds, I run the barrel adjuster all the way in, pull the cable tight, and tighten the pinch bolt. Then I run the RD up to the largest cog, find an exposed bit of cable, and give it two good pulls with my thumb against the frame and my fingers around the cable. I run the RD down to the smallest cog, loosen the pinch bolt, pull the cable tight, and retighten. I do this until I stop getting slack when the RD comes down to the smallest cog, then adjust the indexing. It usually takes 1-2 pulls, but I did 4 on the 920 RD and my shifting still came out of whack on my 8 mile ride home. It was just 1/2 - 2/3 of a barrel adjuster turn, but it seems kind of excessive to me. I'm putting Jagwire Road Pro XL cables and housing on it when my Apex shifters and TRP Spyre brakes get in, so I'm not too concerned.
1) SIZE THE FRAME ON TOP TUBE LENGTH, NOT SEAT TUBE! The stock stem length on all of the 920 sizes is ridiculous. When you look at the geo chart, the 56 (what I normally ride) has a 100mm stem (what I normally ride) but the top tube is 57.8cm long. My 2012 Tricross Sport is 56cm square, and it came stock with a 100mm stem. It's comfortable. The 920 combination of long top tube, long stem, and ridiculously long TRP brake hoods makes this bike feel like a limo. I came into this purchase knowing these things, and also knowing the bars and brake/ shifters were going to be replaced almost immediately. If you're planning on buying a 920 and immediately setting out on a 3,000 mile tour; size the bike on top tube.
2) Your spokes are loose. When the bike comes out of the box, the spokes are loose. The wheels were basically true and round, but tension wasn't as high as I like to see, especially when this bike has been getting lambasted for being an adventure bike with "only" 28 spokes. I think it's a bad idea, and I'm probably going to end up building a 36 hole rear wheel at some point. I also see no evidence of any spoke prep or linseed oil, which is fine by me. I'll do some measuring at work to see if NDS and DS are the same length. I'm hoping they are. Asymmetrical rims are awesome.
3) Your bottom bracket needs faced, and the bottom bracket cups have no loctite on them. I like using the bottom bracket facing tools, so it wasn't a pain for me to remove the BB and face it. It came out of the box decently square, but the paint wasn't uniform thickness around the face. I went very slow and pulled the tool off about every 1/4 turn (Chris King facer with 5 cutting heads, it works pretty quickly). Once I got through the paint, the actual frame itself was faced about 80% around. There was one low spot about 5mm long on the drive side, and a smaller low spot on the NDS. The cranks spun fine, but I felt much better knowing my bike was 100% when I got done with the facing tool. I also stripped the grease off the bottom bracket cup threads and applied loctite 243. We can go around and around about putting loctite on a bottom bracket (especially aluminum cups in an aluminum frame), but the manufacturer, park tool, and barnett's manual all recommend it. It does a great job of keeping the threads pristine, is easy to remove since it's a blue loctite, and it keeps the creak away forever if you install the bottom bracket correctly. I can't say the same for grease or anti-seize, which both wash out in use.
4) The rack bolts don't have loctite on them, either. In a world where almost every bolt on a bicycle comes with pre-applied loctite, I was really surprised to see none on the rack bolts. It was a simple fix for me, but I know most mechanics won't go to the trouble of applying loctite, especially if they're building the bike as a floor model, and not as a special order for a known customer they like. It sucks, but that's how it goes.
5) My stem top cap had been overtightened before it was boxed. there's stress marks all around the outside edge of the cap, right above where the top of the stem sits. there's even a mark where the slot in the stem is. Trek is going to warranty this for me, but it is still something to note.
That was all of the big items I noticed. Anything beyond this is just me being nitpicky, which is easy for me to do.
6) The housing loop on the rear derailleur was too long. It worked fine, and probably wouldn't have gotten caught on anything, but I cut mine about 2 cm shorter. It follows the chainstay much closer now.
7) The cables and housing for both derailleurs seemed to have a lot of stretch. For most builds, I run the barrel adjuster all the way in, pull the cable tight, and tighten the pinch bolt. Then I run the RD up to the largest cog, find an exposed bit of cable, and give it two good pulls with my thumb against the frame and my fingers around the cable. I run the RD down to the smallest cog, loosen the pinch bolt, pull the cable tight, and retighten. I do this until I stop getting slack when the RD comes down to the smallest cog, then adjust the indexing. It usually takes 1-2 pulls, but I did 4 on the 920 RD and my shifting still came out of whack on my 8 mile ride home. It was just 1/2 - 2/3 of a barrel adjuster turn, but it seems kind of excessive to me. I'm putting Jagwire Road Pro XL cables and housing on it when my Apex shifters and TRP Spyre brakes get in, so I'm not too concerned.
11-25-19, 01:24 PM
#4
Señor Member
Join Date: Feb 2013
Posts: 5,066
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 649 Post(s)
Liked 292 Times
in
215 Posts
I am dreaming of a 920 for myself for a do-it-all bike. I, too, would likely build a 32 or 25 spoke rear wheel for it, but making sure the spokes on the stock wheels are properly tensioned will get you 90% there.
Has anyone heard issues with frame durability? I have had very good luck with aluminum bikes in the past, and would be surprised if there had been a problem.
Has anyone heard issues with frame durability? I have had very good luck with aluminum bikes in the past, and would be surprised if there had been a problem.
11-27-19, 04:07 AM
#5
Senior Member
Join Date: Apr 2016
Location: Denmark
Posts: 71
Bikes: 2016 All City Macho Man, 2017 Trek 520, 1997 GT Karakoram
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Likes: 0
Liked 5 Times
in
3 Posts
1) SIZE THE FRAME ON TOP TUBE LENGTH, NOT SEAT TUBE! The stock stem length on all of the 920 sizes is ridiculous. When you look at the geo chart, the 56 (what I normally ride) has a 100mm stem (what I normally ride) but the top tube is 57.8cm long. My 2012 Tricross Sport is 56cm square, and it came stock with a 100mm stem. It's comfortable. The 920 combination of long top tube, long stem, and ridiculously long TRP brake hoods makes this bike feel like a limo. I came into this purchase knowing these things, and also knowing the bars and brake/ shifters were going to be replaced almost immediately. If you're planning on buying a 920 and immediately setting out on a 3,000 mile tour; size the bike on top tube.
12-27-19, 09:43 PM
#6
Pokemon Master
Thread Starter
I found it hard to find the exact type of BB on a Trek 920 beside "sealed cartridge". On another forum I found photos of the older 920 (strange-looking-bottom-bracket-590056.html on mtbr.com). Is your 920 BB still remained the same type? (pardon me on the above link as this bulletin board would not allow me to post pcitures and urls yet)
12-27-19, 09:45 PM
#7
Pokemon Master
Thread Starter
I am dreaming of a 920 for myself for a do-it-all bike. I, too, would likely build a 32 or 25 spoke rear wheel for it, but making sure the spokes on the stock wheels are properly tensioned will get you 90% there.
Has anyone heard issues with frame durability? I have had very good luck with aluminum bikes in the past, and would be surprised if there had been a problem.
Has anyone heard issues with frame durability? I have had very good luck with aluminum bikes in the past, and would be surprised if there had been a problem.
Thread
Thread Starter
Forum
Replies
Last Post
hazex3
Classic and Vintage Bicycles: Whats it Worth? Appraisals.
5
08-30-14 10:12 AM
AlphaDogg
Bicycle Mechanics
15
10-28-11 07:35 PM
