Hi, Chris. I agree with Tom – experiment with those upper bosses even though one of the two bosses is currently blocked by the sidepull of the brake caliper. Before you bend the aluminum strut, determine if a triangle will stop the side-side shimmy.
On the unblocked side, mount the strut normally to the outboard of the boss. On the blocked side, mount one of the struts from the inside of the boss. If it's still a bit blocked by the sidepull, you can use old V-brake cone & cup parts to shim it clear of the brake. (I can't recall how blocked the boss was when I saw it last month.) If that solves the wobble, then bend the strut. You probably only get one chance to bend the aluminum strut before it weakens when you bend it twice. Another possibility is to temporarily switch out the rear brake so you can do your experiment with normal, straight struts with no shims. Next time we meet, I can lend you an old centerpull brake with enough clearance for your chunky tire that will free up lots of space for the struts. If that experiment works, then you have an excuse to buy a Paul Racer for the rear. 😀 Tyler On Thu, Nov 27, 2025 at 11:04 PM TOM CUNNINGHAM <[email protected]> wrote: > > If the side pull is in the way...that's only on the cable side. The other > side is open to experiment with a single strut (HD if available) to see if > that seems to make a difference. > On Thursday, November 27, 2025 at 09:45:39 PM PST, Christopher Young < > [email protected]> wrote: > > > Guy, > > Great questions. > > - Attached is a picture showing the original installation, as done by > Riv. As you can see the back strut connects to a point near the dropout, so > those struts were even longer. And the rack was even higher above the rear > tire. I've got it a bit down and can go a little further. Maybe they put it > high thinking I might add a fender? > - I did add the basket and agree that's contributing to the problem. > i'm planning to move it to the Clem, but note that it's the wald "racing" > basket, so pretty minimal. Note also that in this earlier picture, the > basket isn't there, but I'm pretty darn sure the shimmy had already shown > up. > - I'm definitely going to try to figure a way to connect those forward > struts to the the higher connection points, by the brake. That's going to > be challenging. > - If i do that, and I've still got issues, I may also move the back > struts up to the connection point where the forward ones currently are. > That would seem to be more in line with other installations I've seen in > photos on the Riv site and elsewhere. > - bottom line: I think this weird installation has everything to do > with the brake blocking easy access to the higher attachment points. You'd > use those if you could get to them. I'm a little surprised the Riv guys > didn't tell me this might be a problem and suggest a different rack setup, > but maybe they thought I wouldn't put much weight on the rack (not that > I've been really loading it up). Anyway, I definitely don't blame them. I'm > the one that picked that rack and said to put it on the back. I could have > asked them what they'd recommend for that bike. > > I appreciate all the suggestions! The basket is going for sure, and I'm > very likely going to get a Bagboy, but I still want to try to fix this > issue. It just shouldn't be like this. > > Chris > > On Thu, Nov 27, 2025 at 9:03 PM Guy Jett <[email protected]> wrote: > > So many questions: > * Would be nice to see the original Riv installation. > * Did that installation include the basket or did you add the basket? > * Was the rack initially that high above the rear tire? > > Additional Observation: > * There is basically no triangulation in this setup, especially with the > near vertical angle of the diving board. As a result fore and act > movement may be a contributing factor to the lateral motion and shimmy. > > Suggestions: > * Get rid of the basket. That only contributes extra weight very high up > that exaggerates the shimmy. > * Reduce the height of the rack to 1 cm or less above the tire. Will > shorten the rear stays a bit. > * Connect the forward stays directly to the fittings above the brake. > They will be much shorter and provide better triangulation to the rack > system. > * Get rid of the bend in the left rear stay. Alternatively consider > bending both rear stays inward as this may counteract the lateral motion. > > Hope you find a solution, > GAJett > > > > > On Thu, Nov 27, 2025, 12:13 PM tom butcherboy <[email protected]> wrote: > > Beware of free advice..but. I think your rack might benefit from some > 'fore/aft' connection. it seems mostly side to side. And as the load get > taller, center of gravity rises. Your seat stay eyelets are both raising > their hands looking for work. I had a similar issue when downhill braking > and rebalancing some sort of front-end load was helpful. Tom. > > On Thursday, November 27, 2025 at 11:56:05 AM UTC-8 [email protected] > wrote: > > Hi All, > > I have a 61.5 cm AHH with a rear rack installed by Riv when I bought the > bike. The rack looks great, but I've noticed that when I have it loaded, I > often get a front-end shimmy when I am riding fast and take my hands of the > grips, and people riding behind me have confirmed the rack is moving a lot. > It sounds exactly like what Paul M described in a 2024 post about his 64 cm > Clem: > "I also experienced a front-end shimmy if I took both hands off the > handlebars with a loaded rear rack trunk mounted on the top of the rack". > Exactly!! > > Because of the size of the frame and the way it's installed (see picture), > my theory is that those vertical supports are very long and hence not so > rigid and I'm getting some sort of harmonic motion (like a mini-version of > the Tacoma Narrows bridge). Anyway, I've tried some minor adjustments to > try to make the rack supports shorter and hence more rigid, but with only > minor (if any success). At this point, I'm thinking of a couple of options: > 1. more radically changing the attachment points for the rack to get those > longer supports a lot shorter. This could get tricky though, working around > the rear brake. > 2. Removing the basket (it can go on my newly acquired 64 cm Clem L) and > changing to a rear bag (e.g. Sackville Bagboy) that hangs from the saddle > and hence doesn't really rest all its weight on the rack. I can still strap > lighter stuff on the rack. > > I'm strongly leaning toward option #2 because I like the look of the rack > as is and I think the behind the seat bag might look very nice. I guess > another option is to install a different rear rack with more rigid > supports, but again, I like the look of this rack and this isn't my bike > for hauling heaving loads (that's be the Clem). > > Have others experienced this sort of problem and if so, how did you fix it? > > thanks > > Chris Young > ABQ > > -- > You received this message because you are subscribed to the Google Groups > "RBW Owners Bunch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/d/msgid/rbw-owners-bunch/15fae32a-4bd1-464d-b5a9-13b304bd8de9n%40googlegroups.com > <https://groups.google.com/d/msgid/rbw-owners-bunch/15fae32a-4bd1-464d-b5a9-13b304bd8de9n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > Guy > > -- > You received this message because you are subscribed to a topic in the > Google Groups "RBW Owners Bunch" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/rbw-owners-bunch/G8tosK9y08k/unsubscribe > . > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To view this discussion visit > https://groups.google.com/d/msgid/rbw-owners-bunch/CAMHQv6XuTqMO%2BrWJshbJrWuwx96zSZk%3DQP8fAobxrZOou%2Boh6Q%40mail.gmail.com > <https://groups.google.com/d/msgid/rbw-owners-bunch/CAMHQv6XuTqMO%2BrWJshbJrWuwx96zSZk%3DQP8fAobxrZOou%2Boh6Q%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > -- > You received this message because you are subscribed to the Google Groups > "RBW Owners Bunch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > > https://groups.google.com/d/msgid/rbw-owners-bunch/CAC_3U-3xe9wvm-ty827XMGgRH1FccqM9tN4LiZwKNtcH9MAVGA%40mail.gmail.com > <https://groups.google.com/d/msgid/rbw-owners-bunch/CAC_3U-3xe9wvm-ty827XMGgRH1FccqM9tN4LiZwKNtcH9MAVGA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > -- > You received this message because you are subscribed to the Google Groups > "RBW Owners Bunch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/d/msgid/rbw-owners-bunch/722853842.1544627.1764309835320%40mail.yahoo.com > <https://groups.google.com/d/msgid/rbw-owners-bunch/722853842.1544627.1764309835320%40mail.yahoo.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/rbw-owners-bunch/CAPQ3yx5Fo9q9zzx0XWA3P7f6%3DY4RbiY-gwGnb5_yNYgARcPmpw%40mail.gmail.com.
