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2

In the end, what I chose to do was stay conservative and utilizing some hand tools and a makeshift jig, I filed the galled aluminum away off the edge of the left hand bottom bracket shell. I took it just down to the original edge where the spacer of the stolen BB butted against. I used digital calipers frequently around the entire circumference to check the ...


2

As others have said there is basically no good way to add additional structure to the front wheel to triangulate the support for it without lots of extra weight and complications to allow it to turn and steer the bike. It turns out we can make forks that are good enough without triangulation. Also bear in mind that the rear part of a bike frame has to ...


1

Sorry serial numbers are only helpful if you already know the manufacturer AND they used some kind of system, AND kept records AND EITHER those records are available for searching, OR someone has figured+published the encoding system. As it stands, I see a BMX frame with rear brake mounts for either U brakes or possibly V brakes if its more recent. This ...


1

A triangle is a truss. Old bikes had trusses front and back. Two (seat tube - chain stay - seat stay), and one (seat tube, down tube top tube). As bikes and materials and construction methods have evolved manufacturers were able to develop designs that are not trusses - either by beefing up a single tube or some other geometry. Suspension systems have ...


5

Forks on bikes and motorcycles do pay either a weight or stiffness/strength penalty for their lack of triangulation. One can imagine systems for steering the front hub with a linkage rather than a conventional cantilevered fork. That sounds more heavy and complex than it's worth for a bicycle once you have it able to handle the full range of motion needed, ...


1

They are not necessarily stiffer in the back merely because that section more closely resembles a triangle. The geometry and structure of a bicycle is more complex than that.The primary purpose of a bike frame is to hold your weight over the wheels, stiffness isn't the main goal. A relative amount of stiffness is necessary, but a little flex is good too. ...


4

If the fork was also welded to the frame at the bottom, you would not be able to steer. There are still two points of contact to the headset, the down tube and the top tube. Also, the fork needs to be compliant and not totally stiff for good riding properties, otherwise the ride is too harsh and braking could also be bad. In the back it works differently. ...


4

Roadmaster Techno Trac. Sears never made bikes, they bought them from other companies like Steyr, AMF-Roadmaster and Murray. see one here with the original decals still intact (and a broken frame) https://www.flickr.com/photos/rickpaulos/49958454372/


2

This Cyclingtips podcast contains an interview with Ruckus Composites, which repairs carbon frames. To be honest, I listened to it a week ago and I don't recall the details of the contents. I do recall that there is a lot of thought that goes into properly repairing any structural carbon damage. They have to consider how much to reinforce the damaged area, ...


8

Most of that damage is through the paint, but there are obviously some gouges in the surface of the carbon fiber composite itself. I think if you want to be sure that a repair is good you will have to consult a professional CFC repair shop. Chances are they can sand off the paint, smooth the area and lay a patch over the damage.


8

A Possible match and a caution. Possible Match It looks like a NEXT Gauntlet from Walmart. They were made with both 24" and 26" wheels Caution In the picture your stem looks very high. Please check to make sure it's safe to ride. On a handlebar stem there is usually a horizontal line stamped in the metal and the word "MAX" - or something like that. ...


2

It is not important who made the bike. What is important is what parts it features. Your bike has: a quill stem, spring-based full suspension, V-brakes, a padded wide saddle, kick stand, rear derailleur protector, spoke protector, non-quick-release axles. All are things typically put on supermarket-type bikes (sometimes called BSO). Cranks will probably be ...


5

It looks like a 2017 Giant Contend SL2 Disc: https://www.giant-bicycles.com/gb/contend-sl-2-disc-2017. The picture is quite grainy so it's hard to be 100% sure. Check if it has the Giant Conduct disc brake system to be sure. Here's the image in the linked product page for the 2017 Giant Contend SL2 Disc:


7

You should ask the seller for all the information you need about the bike, because a) they should know more than we do and b) if they can't give it to you readily then there is more risk that it is stolen. These things do happen! Don't tell the seller this, but the name is usually written on the frame. If they can't manage that much then consider walking ...


2

Looks like a nice bike - not very old because disk brakes have only been on road bikes in the last ~5 years. The top tube profile suggests an aluminium frame not carbon fibre, and the thickness of the fork tines/legs suggest they are carbon fibre. Both tyres are a bit low on air so pump them up before you test-ride it. And you should absolutely test ride ...


2

TL;DR: Headset cups are more play-safe, but the IS headset is simpler to 'fit', and though the mass manufacturing industry is as 'unsophisticated' as ever, most consumers don't care much anyways. It'll wear out eventually, but nothing much to worry about unless you do a hundred barspins every day. My long gibberish: From a layman's and manufacturer's ...


2

The head tube angle is the same, the seat tube angle is the same, so raising or lowering stem and or seat post will be no different regardless if it is a traditional or compact. The difference is the amount of adjustability. A compact frame means a shorter seat tube and head tube and a steerer tube which is relatively long compared to the head tube. This ...


2

The claim is pure marketing and does not make any sense at all, unless you only care about standover height. It is true that Giant has smaller selection of sizes than competing manufacturers, and Giant might use the claim to explain why, but even their own models are not consistent with the explanation: High end Giant models have 6, not 3 frame sizes. This ...


4

If it's rubbing while riding, but not when you're off the bike, it's either a spoke tension issue as noted by @earlgrey, or, you could have loose bearing cones that are allowing your wheel to flop around. Either way, a dangerous condition that you should have a local shop look into.


1

What size adult tricycle? Sizing a bike is about getting a bike that fits your height and body proportions. For an adult tricycle frame and wheel sizes are not a factor in fitting the vehicle to the person like they are with bicycles. Small wheel sizes on a trike help the rider get on or off the bike. Larger wheel sizes generally aid in riding longer ...


2

Here is a picture from a 1985 catalog that is a fair (not excellent) match for brand, type, color, seat (stripes?), crank. Was 1985 the only year they offered this bike? I doubt it. I know that the 1985 Specialized Stumpjumper Team had a rear brake configuration similar to the one in the original post, so 1985 is not impossible. The Piemonte pictured above ...


4

It is an early 90's steel rigid MTB. That model of BIOPACE chainring dates it to 1989-1993, as does the Shimano Exage groupset was released first in 1988/9 with a last year of 1993. These parts can be replaced, but given the bike's lack of wear they're probably original The plastic spoke protector isn't broken so it has not had a hard life. The only ...


3

It didn't leave a factory like that. From the area around the rear handlebars you can see it's been modified. A head tube (blue rather than the black of the rest of the frame) has been welded to the front seat post, reversed. I suspect the rear top tube has been cut off, weakening the frame a lot, and the steerer parts attached to the stub of that. It ...


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