mounting best practices and carrying capacity of rear racks
#1
Senior Member
Thread Starter
Join Date: Sep 2012
Posts: 142
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
Likes: 0
Liked 4 Times
in
2 Posts
mounting best practices and carrying capacity of rear racks
I have an oldish road bike outfitted with fenders and a rear rack. Both of those I purchased separately and the rear fend and the rack are sharing the same eyelets for mounting. I had to go and get longer 5mm bolts, threw some lock washers on as well and all seems to be well. What worries me slightly is that fender stays naturally want to be on the inside (closer to chain stays), while the rack stays are stacked on the outside, closer to the bolt cap. So far, all's good (been carrying all kinds of cargo and just had about 40lbs of groceries and chain on a short trip without issues), but mechanically this isn't ideal.
The reason it's not ideal is because the really heavy bit is pushing down on the whole assembly further away than perhaps it was designed for from the point it wants to bend/pivot the bolt around. Attaching a crude diagram, if the text isn't clear:
My question is whether these kinds of installations are common and if people are having any issues with heavy cargo placing large stresses on 2 relatively skinny little bolts. I hope to take a multi-day tour alone with this bike in the months to come and am wondering if I need to buttress this configuration or just bring some spare hardware with me.
The reason it's not ideal is because the really heavy bit is pushing down on the whole assembly further away than perhaps it was designed for from the point it wants to bend/pivot the bolt around. Attaching a crude diagram, if the text isn't clear:
My question is whether these kinds of installations are common and if people are having any issues with heavy cargo placing large stresses on 2 relatively skinny little bolts. I hope to take a multi-day tour alone with this bike in the months to come and am wondering if I need to buttress this configuration or just bring some spare hardware with me.
#2
aka Phil Jungels
I think you are over worrying. I've had some pretty hefty loads on there, without issue.
#3
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2026 Post(s)
Likes: 0
Liked 1,096 Times
in
742 Posts
Basically your concern is well founded and the rack stay should be placed inboard of the fender stay to reduce the load's leverage on pretty thin 5 mm bolts. I'd "customize" (read: bend) the stays as needed to get the rack supports inboard.
#4
Senior Member
There nothing wrong with your set up , people do it all the time . Just make sure the bolts are tight . If in drought use some blue loc-tide on the bolts .
#5
Really Old Senior Member
Whichever way you go, keep an eye on the screws to make sure they remain tight.
I have double eyelets on my 86 Rockhopper and a rack & fender set up is still a pain.
Maybe get a set of fenders for bikes with no eyelet mounting? I'd hate to see you "wallow out" the eyelets.
I have double eyelets on my 86 Rockhopper and a rack & fender set up is still a pain.
Maybe get a set of fenders for bikes with no eyelet mounting? I'd hate to see you "wallow out" the eyelets.
#6
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,715
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5784 Post(s)
Liked 2,578 Times
in
1,429 Posts
If there's any way you can reverse these, do so and you'll have a more secure arrangement. Otherwise use heat-treated chrome-moly cap screws, or at least quality stainless once, instead of the typical standard hardware. If you're planning a long tour carry spares.
One trick, if you cannot pass the fenders outside the rack, is to place the left leg of the rack inside the dropout, with the fender outside. If you do this pass the bolt from the inside outward with a nut to retain the fender stays. That way your rack won't fall down if the nut loosens and falls off.
The beauty of this is that at least one leg of the rack is better secured.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#7
Banned
When in doubt head over to the Auto Parts store , ask for the same sized bolt in 8.8 type,
a high strength heat treated alloy steel .. It will be stamped on the hex head.
get properly tight and use a threadlock compound.
a high strength heat treated alloy steel .. It will be stamped on the hex head.
get properly tight and use a threadlock compound.
#8
Senior Member
Thread Starter
Join Date: Sep 2012
Posts: 142
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
Likes: 0
Liked 4 Times
in
2 Posts
Thanks for the ideas, folks! Looks like my worry isn't needless, though the sky isn't falling just yet. I'll try to reverse rack and fender stays and if that doesn't work, I'll get some stronger bolts and some spares.
#9
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,715
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5784 Post(s)
Liked 2,578 Times
in
1,429 Posts
Do both, you can never go wrong with high quality hardware.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#10
Hello
You could also carry some p clips and hardware for back up. But under normal use scenario ( let's say 30 pounds riding on paved roads) I don't think you would need them.
#11
Senior Member
Thread Starter
Join Date: Sep 2012
Posts: 142
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
Likes: 0
Liked 4 Times
in
2 Posts
Was looking at the assembly today and realized there would be no easy way to swap the stays in place due to the available length of fender stays and where they want to intersect with the rack. But then I got another idea.
The holes in the frame let the bolts come out the other side and it looks like it'll be possible to have the bolt cap squeeze the rack stays to the frame, while the fender stays can be squeezed to the frame from the other side (from the inside of the bike) by a nut and washer. Think I'll try that next time I can make it to a hardware store.
The holes in the frame let the bolts come out the other side and it looks like it'll be possible to have the bolt cap squeeze the rack stays to the frame, while the fender stays can be squeezed to the frame from the other side (from the inside of the bike) by a nut and washer. Think I'll try that next time I can make it to a hardware store.
#12
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,715
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5784 Post(s)
Liked 2,578 Times
in
1,429 Posts
Was looking at the assembly today and realized there would be no easy way to swap the stays in place due to the available length of fender stays and where they want to intersect with the rack. But then I got another idea.
The holes in the frame let the bolts come out the other side and it looks like it'll be possible to have the bolt cap squeeze the rack stays to the frame, while the fender stays can be squeezed to the frame from the other side (from the inside of the bike) by a nut and washer. Think I'll try that next time I can make it to a hardware store.
The holes in the frame let the bolts come out the other side and it looks like it'll be possible to have the bolt cap squeeze the rack stays to the frame, while the fender stays can be squeezed to the frame from the other side (from the inside of the bike) by a nut and washer. Think I'll try that next time I can make it to a hardware store.
While a locker rear wheel isn't as critical as a locked front wheel, it's no picnic if it happens at speed.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#13
Senior Member
Thread Starter
Join Date: Sep 2012
Posts: 142
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
Likes: 0
Liked 4 Times
in
2 Posts
This is what I suggested earlier, but a bit of safety advice. If bolting to the inside of fender eyes, put the head of the bolt on the inside, and nuts and washers on the outside. This provides minimum possibility of stuff getting loose between the frame and wheel, thereby lessening the chances of something slipping into and jamming the wheel.
While a locker rear wheel isn't as critical as a locked front wheel, it's no picnic if it happens at speed.
While a locker rear wheel isn't as critical as a locked front wheel, it's no picnic if it happens at speed.
I was thinking about that too. What I like about having the bolt cap on the outside is that if a nut gets loose, the fender will likely rub against the tire, but will not cause much other trouble because the bolt itself will still be tight against the rack stay. On the other hand, if a nut on the outside gets loose, it may cause the loaded rack to slip off the bolt and tweak itself, dislodge the luggage or who knows what else. But your concern is valid and what I think I'll do to mitigate that risk of wheel entanglement is to put some reasonably tight plastic zip ties around fender stays and frame so as to keep them close to their intended position in case of nuts coming loose.
#14
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,715
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5784 Post(s)
Liked 2,578 Times
in
1,429 Posts
Ah, sorry. Missed your comment somehow. Thank you.
I was thinking about that too. What I like about having the bolt cap on the outside is that if a nut gets loose, the fender will likely rub against the tire, but will not cause much other trouble because the bolt itself will still be tight against the rack stay. On the other hand, if a nut on the outside gets loose, it may cause the loaded rack to slip off the bolt and tweak itself, dislodge the luggage or who knows what else. But your concern is valid and what I think I'll do to mitigate that risk of wheel entanglement is to put some reasonably tight plastic zip ties around fender stays and frame so as to keep them close to their intended position in case of nuts coming loose.
I was thinking about that too. What I like about having the bolt cap on the outside is that if a nut gets loose, the fender will likely rub against the tire, but will not cause much other trouble because the bolt itself will still be tight against the rack stay. On the other hand, if a nut on the outside gets loose, it may cause the loaded rack to slip off the bolt and tweak itself, dislodge the luggage or who knows what else. But your concern is valid and what I think I'll do to mitigate that risk of wheel entanglement is to put some reasonably tight plastic zip ties around fender stays and frame so as to keep them close to their intended position in case of nuts coming loose.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#15
rebmeM roineS
Join Date: Jan 2006
Location: Metro Indy, IN
Posts: 16,216
Bikes: Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 653 Post(s)
Liked 347 Times
in
226 Posts
I have seen aluminum machine screws/bolts included with racks in the past. Make sure to use steel, as previously mentioned.
__________________
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
Bacchetta Giro A20, RANS V-Rex, RANS Screamer
#16
Full Member
Join Date: May 2012
Location: Atlanta, GA
Posts: 335
Bikes: Dave Kirk Custom, Clockwork Bikes Custom, Batavus Course Specialized HardRock x2 Trek 700 MultiTrack 1991 Trek 950 SingleTrack. Miyata Three Ten
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 32 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
On the two bikes I have with racks, I mount the racks to the seatpost binder bolt. With a 16 inch frame (c-c), it allows me to not bend the supports at all (which I think has to be stronger than bending them down to hit the seatstay mounts). Furthermore, when I carry my cable lock, I can wrap it twice around the seatpost and those rack supports hold it high enough to keep it from interfering with the cantilever brakes. Someone remarked to me the other day that the setup looked 'strange' but to me it seems a better alternative than bending the supports to mount on the seat stays.
Thread
Thread Starter
Forum
Replies
Last Post
bikecommuter13
Bicycle Mechanics
11
11-10-15 04:51 PM
Roll-Monroe-Co
Bicycle Mechanics
6
10-15-11 07:57 PM